Viewport Size Code:
Login | Create New Account
picture

  MENU

About | Classical Genetics | Timelines | What's New | What's Hot

About | Classical Genetics | Timelines | What's New | What's Hot

icon

Bibliography Options Menu

icon
QUERY RUN:
HITS:
PAGE OPTIONS:
Hide Abstracts   |   Hide Additional Links
NOTE:
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Paleontology Meets Genomics — Sequencing Ancient DNA

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.

More About:  ESP | OUR CONTENT | THIS WEBSITE | WHAT'S NEW | WHAT'S HOT

ESP: PubMed Auto Bibliography 23 Nov 2020 at 01:44 Created: 

Paleontology Meets Genomics — Sequencing Ancient DNA

The ideas behind Jurassic Park have become real, kinda sorta. It is now possible to retrieve and sequence DNA from ancient specimens. Although these sequences are based on poor quality DNA and thus have many inferential steps (i,e, the resulting sequence is not likely to be a perfect replica of the living DNA), the insights to be gained from paleosequentcing are nonetheless great. For example, paleo-sequencing has shown that Neanderthal DNA is sufficiently different from human DNA as to be reasonably considered as coming from a different species.

Created with PubMed® Query: "ancient DNA" OR "ancient genome" OR paleogenetic OR paleogenetics NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

-->

RevDate: 2020-11-21

Gregory MD, Kippenhan JS, Kohn P, et al (2020)

Neanderthal-derived genetic variation is associated with functional connectivity in the brains of living humans.

Brain connectivity [Epub ahead of print].

Aim: To determine whether Neanderthal-derived genetic variation relates to functional connectivity patterns in the brains of living modern humans. Introduction: Nearly 50,000 years ago, Neanderthals interbred with ancestors of modern humans, imparting a genetic legacy that lives on today. The vestiges of this Neanderthal-derived genetic variation have been previously shown to be enriched in genes coding for neurogenesis and myelination and to alter skull shape and brain structure in living people. Methods: Using two independent cohorts totaling 553 healthy individuals, we employed multivariate distance matrix regression (MDMR) to determine whether any brain areas exhibited whole-brain functional connectivity patterns that significantly related to the degree of Neanderthal introgression. Identified clusters were then used as regions-of-interest in follow-up seed-based functional connectivity analyses to determine the connectivity patterns driving the relationships. Results: The MDMR analysis revealed that the percentage of Neanderthal-originating polymorphisms was significantly associated with the functional connectivity patterns of an area of the intraparietal sulcus (IPS) that was nearly identical in both cohorts. Using these IPS clusters as regions-of-interest in seed-based connectivity analyses, we found, again in both cohorts, that individuals with a higher proportion of Neanderthal-derived genetic variation showed increased IPS functional connectivity with visual processing regions, but decreased IPS connectivity with regions underlying social cognition. Conclusions: These findings demonstrate that the remnants of Neanderthal admixture continue to influence human brain function today, in ways that are consistent with anthropological conceptualizations of Neanderthal phenotypes, including the possibility that Neanderthals may have depended upon visual processing capabilities at the expense of social cognition and this may have contributed to the extinction of this species via reduced cultural maintenance and inability to cope with fluctuating resources. This and other work capitalizing on the emerging science surrounding ancient DNA provides a window through which to view an ancient lineage long past.

RevDate: 2020-11-19

Latorre SM, Lang PLM, Burbano HA, et al (2020)

Isolation, Library Preparation, and Bioinformatic Analysis of Historical and Ancient Plant DNA.

Current protocols in plant biology, 5(4):e20121.

The ability to sequence DNA retrieved from ancient and historical material plays a crucial role in reinforcing evolutionary and anthropological inference. While the focus of the field is largely on analyzing DNA from ancient hominids and other animals, we have also learned from plant ancient DNA (aDNA), in particular, about human farming practices, crop domestication, environment management, species invasion, and adaptation to various environmental conditions. In the following protocols, we outline best practices for plant aDNA isolation, preparation for sequencing, bioinformatic processing, and authentication. We describe the process all the way from processing of archaeological or historical plant material to characterizing and authenticating sequencing reads. In alternative protocols, we include modifications to this process that are tailored to strongly degraded DNA. Throughout, we stress the importance of precautionary measures to successfully analyze aDNA. Finally, we discuss the evolution of the archaeogenomics field and the development of new methods, which both shaped this protocol. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Isolation of aDNA Alternate Protocol 1: Isolation of ultra-short DNA (Dabney modification) Support Protocol 1: Preparation of PTB-based mix Support Protocol 2: Preparation of binding buffer Basic Protocol 2: Preparation of genomic libraries Alternate Protocol 2: Preparation of genomic libraries with uracil removal Basic Protocol 3: Bioinformatic processing and authentication of aDNA.

RevDate: 2020-11-18

Roca-Rada X, Souilmi Y, Teixeira JC, et al (2020)

Ancient DNA Studies in Pre-Columbian Mesoamerica.

Genes, 11(11): pii:genes11111346.

Mesoamerica is a historically and culturally defined geographic area comprising current central and south Mexico, Belize, Guatemala, El Salvador, and border regions of Honduras, western Nicaragua, and northwestern Costa Rica. The permanent settling of Mesoamerica was accompanied by the development of agriculture and pottery manufacturing (2500 BCE-150 CE), which led to the rise of several cultures connected by commerce and farming. Hence, Mesoamericans probably carried an invaluable genetic diversity partly lost during the Spanish conquest and the subsequent colonial period. Mesoamerican ancient DNA (aDNA) research has mainly focused on the study of mitochondrial DNA in the Basin of Mexico and the Yucatán Peninsula and its nearby territories, particularly during the Postclassic period (900-1519 CE). Despite limitations associated with the poor preservation of samples in tropical areas, recent methodological improvements pave the way for a deeper analysis of Mesoamerica. Here, we review how aDNA research has helped discern population dynamics patterns in the pre-Columbian Mesoamerican context, how it supports archaeological, linguistic, and anthropological conclusions, and finally, how it offers new working hypotheses.

RevDate: 2020-11-17

Wang T, Dong Q, Wang W, et al (2020)

Evolution of AITR family genes in cotton and their functions in abiotic stress tolerance.

Plant biology (Stuttgart, Germany) [Epub ahead of print].

Abiotic stresses are major environmental factors inhibiting plant growth and development. AITRs (ABA-induced transcription repressors) are a novel family of transcription factors regulating ABA (abscisic acid) signaling and plant responses to abiotic stresses in Arabidopsis. However, the composition and evolution history of AITRs and their roles in cotton genus are largely unknown. Here, a total of 12 putative AITR genes were identified in cultivated tetraploid cotton Gossypium hirsutum. Phylogenetic analysis of GhAITRs in these cottons and their closely related species implicate the ancient genome-wide duplication occurring after speciation of Gossypium and Theobroma could generate the duplicates of GhAITRs. Duplicated GhAITRs were stably inherited in following diploid speciation and further allotetraploidy in Gossypium. Homologous GhAITRs shared common expression patterns in response to ABA, drought and salinity treatments, and drought tolerance could be affected in transgenic Arabidopsis plants expressing GhAITR-A1. Together, our findings reveal that duplicates in GhAITR gene family were achieved by whole genome duplication rather than three individual duplication events, and GhAITRs function as transcription repressors and are involved in the regulation of plant responses to ABA and drought stress. These results may provide insights towards the improvement of abiotic stress tolerance in cotton by using GhAITRs.

RevDate: 2020-11-15

Froment C, Zanolli C, Hourset M, et al (2020)

Comparison of human and non-human primate tooth proteomes as a basis for the study of ancient proteins.

Journal of proteomics pii:S1874-3919(20)30413-9 [Epub ahead of print].

In the context of human evolution, the study of proteins may overcome the limitation of the high degradation of ancient DNA over time to provide biomolecular information useful for the phylogenetic reconstruction of hominid taxa. In this study, we used a shotgun proteomics approach to compare the tooth proteomes of extant human and non-human primates (gorilla, chimpanzee, orangutan and baboon) in order to search for a panel of peptides able to discriminate between taxa and further help reconstructing the evolutionary relationships of fossil primates. Among the 25 proteins shared by the five genera datasets, we found a combination of peptides with sequence variations allowing to differentiate the hominid taxa in the proteins AHSG, AMBN, APOA1, BGN, C9, COL11A2, COL22A1, COL3A1, DSPP, F2, LUM, OMD, PCOLCE and SERPINA1. The phylogenetic tree confirms the placement of the samples in the appropriate genus branches. Altogether, the results provide experimental evidence that a shotgun proteomics approach on dental tissue has the potential to detect taxonomic variation, which is promising for future investigations of uncharacterized and/or fossil hominid/hominin specimens. SIGNIFICANCE: A shotgun proteomics approach on human and non-human primate teeth allowed to identify peptides with taxonomic interest, highlighting the potential for future studies on hominid fossils.

RevDate: 2020-11-12

Bonsu DOM, Higgins D, Henry J, et al (2020)

Evaluation of the efficiency of Isohelix™ and Rayon swabs for recovery of DNA from metal surfaces.

Forensic science, medicine, and pathology pii:10.1007/s12024-020-00329-x [Epub ahead of print].

PURPOSE: We investigated the recovery and extraction efficiency of DNA from three metal surfaces (brass, copper, steel) relevant to forensic casework, and plastic (control) using two different swabbing systems; Rayon and Isohelix™ swabs, with sterile water and isopropyl alcohol respectively, as the wetting solutions.

METHODS: Twenty nanograms of human genomic DNA were applied directly to Isohelix™ and Rayon swabs; and to the metal and plastic substrates. All substrates were left to dry for 24 h, followed by single wet swabbing and extraction with the DNA IQ™ System. DNA extracts were quantified using real time quantitative PCR assays with SYBR green chemistry.

RESULTS: DNA was extracted from directly seeded Isohelix™ swabs with a high efficiency of 98%, indicating effective DNA-release from the swab into the extraction buffer. In contrast, only 58% of input DNA was recovered from seeded Rayon swabs, indicating higher DNA retention by these swabs. Isohelix™ swabs recovered 32 - 53% of DNA from metal surfaces, whilst the Rayon swabs recovered 11-29%. DNA recovery was lowest from copper and highest from brass. Interestingly, Rayon swabs appeared to collect more DNA from the plastic surface than Isohelix™ swabs, however, due to the lower release of DNA from Rayon swabs they returned less DNA overall following extraction than Isohelix™ swabs.

CONCLUSION: These results demonstrate that DNA samples deposited on metal surfaces can be more efficiently recovered using Isohelix™ swabs wetted with isopropyl alcohol than Rayon swabs wetted with sterile water, although recovery is affected by the substrate type.

RevDate: 2020-11-12

Silva M, Pratas D, AJ Pinho (2020)

Efficient DNA sequence compression with neural networks.

GigaScience, 9(11):.

BACKGROUND: The increasing production of genomic data has led to an intensified need for models that can cope efficiently with the lossless compression of DNA sequences. Important applications include long-term storage and compression-based data analysis. In the literature, only a few recent articles propose the use of neural networks for DNA sequence compression. However, they fall short when compared with specific DNA compression tools, such as GeCo2. This limitation is due to the absence of models specifically designed for DNA sequences. In this work, we combine the power of neural networks with specific DNA models. For this purpose, we created GeCo3, a new genomic sequence compressor that uses neural networks for mixing multiple context and substitution-tolerant context models.

FINDINGS: We benchmark GeCo3 as a reference-free DNA compressor in 5 datasets, including a balanced and comprehensive dataset of DNA sequences, the Y-chromosome and human mitogenome, 2 compilations of archaeal and virus genomes, 4 whole genomes, and 2 collections of FASTQ data of a human virome and ancient DNA. GeCo3 achieves a solid improvement in compression over the previous version (GeCo2) of $2.4\%$, $7.1\%$, $6.1\%$, $5.8\%$, and $6.0\%$, respectively. To test its performance as a reference-based DNA compressor, we benchmark GeCo3 in 4 datasets constituted by the pairwise compression of the chromosomes of the genomes of several primates. GeCo3 improves the compression in $12.4\%$, $11.7\%$, $10.8\%$, and $10.1\%$ over the state of the art. The cost of this compression improvement is some additional computational time (1.7-3 times slower than GeCo2). The RAM use is constant, and the tool scales efficiently, independently of the sequence size. Overall, these values outperform the state of the art.

CONCLUSIONS: GeCo3 is a genomic sequence compressor with a neural network mixing approach that provides additional gains over top specific genomic compressors. The proposed mixing method is portable, requiring only the probabilities of the models as inputs, providing easy adaptation to other data compressors or compression-based data analysis tools. GeCo3 is released under GPLv3 and is available for free download at https://github.com/cobilab/geco3.

RevDate: 2020-11-10

Thomas C, Francke A, Vogel H, et al (2020)

Weak Influence of Paleoenvironmental Conditions on the Subsurface Biosphere of Lake Ohrid over the Last 515 ka.

Microorganisms, 8(11): pii:microorganisms8111736.

Lacustrine sediments are widely used to investigate the impact of climatic change on biogeochemical cycling. In these sediments, subsurface microbial communities are major actors of this cycling but can also affect the sedimentary record and overprint the original paleoenvironmental signal. We therefore investigated the subsurface microbial communities of the oldest lake in Europe, Lake Ohrid (North Macedonia, Albania), to assess the potential connection between microbial diversity and past environmental change using 16S rRNA gene sequences. Along the upper ca. 200 m of the DEEP site sediment record spanning ca. 515 thousand years (ka), our results show that Atribacteria, Bathyarchaeia and Gammaproteobacteria structured the community independently from each other. Except for the latter, these taxa are common in deep lacustrine and marine sediments due to their metabolic versatility adapted to low energy environments. Gammaproteobacteria were often co-occurring with cyanobacterial sequences or soil-related OTUs suggesting preservation of ancient DNA from the water column or catchment back to at least 340 ka, particularly in dry glacial intervals. We found significant environmental parameters influencing the overall microbial community distribution, but no strong relationship with given phylotypes and paleoclimatic signals or sediment age. Our results support a weak recording of early diagenetic processes and their actors by bulk prokaryotic sedimentary DNA in Lake Ohrid, replaced by specialized low-energy clades of the deep biosphere and a marked imprint of erosional processes on the subsurface DNA pool of Lake Ohrid.

RevDate: 2020-11-09

Psonis N, de Carvalho CN, Figueiredo S, et al (2020)

Molecular identification and geographic origin of a post-Medieval elephant finding from southwestern Portugal using high-throughput sequencing.

Scientific reports, 10(1):19252 pii:10.1038/s41598-020-75323-y.

Molecular species identification plays a crucial role in archaeology and palaeontology, especially when diagnostic morphological characters are unavailable. Molecular markers have been used in forensic science to trace the geographic origin of wildlife products, such as ivory. So far, only a few studies have applied genetic methods to both identify the species and circumscribe the provenance of historic wildlife trade material. Here, by combining ancient DNA methods and genome skimming on a historical elephantid tooth found in southwestern Portugal, we aimed to identify its species, infer its placement in the elephantid phylogenetic tree, and triangulate its geographic origin. According to our results the specimen dates back to the eighteenth century CE and belongs to a female African forest elephant (non-hybrid Loxodonta cyclotis individual) geographically originated from west-west-central Africa, from areas where one of the four major mitochondrial clades of L. cyclotis is distributed. Historical evidence supports our inference, pointing out that the tooth should be considered as post-Medieval raw ivory trade material between West Africa and Portugal. Our study provides a comprehensive approach to study historical products and artefacts using archaeogenetics and contributes towards enlightening cultural and biological historical aspects of ivory trade in western Europe.

RevDate: 2020-11-09

Teschler-Nicola M, Fernandes D, Händel M, et al (2020)

Ancient DNA reveals monozygotic newborn twins from the Upper Palaeolithic.

Communications biology, 3(1):650 pii:10.1038/s42003-020-01372-8.

The Upper Palaeolithic double burial of newborns and the single burial of a ca. 3-month-old infant uncovered at the Gravettian site of Krems-Wachtberg, Austria, are of paramount importance given the rarity of immature human remains from this time. Genome-wide ancient DNA shows that the male infants of the double grave are the earliest reported case of monozygotic twins, while the single grave´s individual was their 3rd-degree male relative. We assessed the individuals´ age at death by applying histological and µCT inspection of the maxillary second incisors (i2) in conjunction with C- and N-isotope ratios and Barium (Ba) intake as biomarker for breastfeeding. The results show that the twins were full-term newborns, and that while individual 2 died at birth, individual 1 survived for about 50 days. The findings show that Gravettian mortuary behaviour also included re-opening of a grave and manipulation of its layout and content.

RevDate: 2020-11-06

Jeong C, Wang K, Wilkin S, et al (2020)

A Dynamic 6,000-Year Genetic History of Eurasia's Eastern Steppe.

Cell pii:S0092-8674(20)31321-0 [Epub ahead of print].

The Eastern Eurasian Steppe was home to historic empires of nomadic pastoralists, including the Xiongnu and the Mongols. However, little is known about the region's population history. Here, we reveal its dynamic genetic history by analyzing new genome-wide data for 214 ancient individuals spanning 6,000 years. We identify a pastoralist expansion into Mongolia ca. 3000 BCE, and by the Late Bronze Age, Mongolian populations were biogeographically structured into three distinct groups, all practicing dairy pastoralism regardless of ancestry. The Xiongnu emerged from the mixing of these populations and those from surrounding regions. By comparison, the Mongols exhibit much higher eastern Eurasian ancestry, resembling present-day Mongolic-speaking populations. Our results illuminate the complex interplay between genetic, sociopolitical, and cultural changes on the Eastern Steppe.

RevDate: 2020-11-06
CmpDate: 2020-11-06

Callaway E (2020)

Ancient dog DNA reveals 11,000 years of canine evolution.

Nature, 587(7832):20.

RevDate: 2020-11-10
CmpDate: 2020-11-10

Laza IM, Hervella M, Neira Zubieta M, et al (2019)

Environmental factors modulated ancient mitochondrial DNA variability and the prevalence of rheumatic diseases in the Basque Country.

Scientific reports, 9(1):20380.

Among the factors that would explain the distribution of mitochondrial lineages in Europe, climate and diseases may have played an important role. A possible explanation lies in the nature of the mitochondrion, in which the energy generation process produces reactive oxygen species that may influence the development of different diseases. The present study is focused on the medieval necropolis of San Miguel de Ereñozar (13th-16th centuries, Basque Country), whose inhabitants presented a high prevalence of rheumatic diseases and lived during the Little Ice Age (LIA). Our results indicate a close relationship between rheumatic diseases and mitochondrial haplogroup H, and specifically between spondyloarthropathies and sub-haplogroup H2. One possible explanation may be the climate change that took place in the LIA that favoured those haplogroups that were more energy-efficient, such as haplogroup H, to endure lower temperatures and food shortage. However, it had a biological trade-off: the increased risk of developing rheumatic diseases.

RevDate: 2020-11-05

Abbona CC, Adolfo GN, Johnson J, et al (2020)

Were domestic camelids present on the prehispanic South American agricultural frontier? An ancient DNA study.

PloS one, 15(11):e0240474 pii:PONE-D-20-06090.

The southern boundary of prehispanic farming in South America occurs in central Mendoza Province, Argentina at approximately 34 degrees south latitude. Archaeological evidence of farming includes the recovery of macrobotanical remains of cultigens and isotopic chemistry of human bone. Since the 1990s, archaeologists have also hypothesized that the llama (Lama glama), a domesticated South American camelid, was also herded near the southern boundary of prehispanic farming. The remains of a wild congeneric camelid, the guanaco (Lama guanicoe), however, are common in archaeological sites throughout Mendoza Province. It is difficult to distinguish bones of the domestic llama from wild guanaco in terms of osteological morphology, and therefore, claims that llama were in geographic areas where guanaco were also present based on osteometric analysis alone remain equivocal. A recent study, for example, claimed that twenty-five percent of the camelid remains from the high elevation Andes site of Laguna del Diamante S4 were identified based on osteometric evidence as domestic llama, but guanaco are also a likely candidate since the two species overlap in size. We test the hypothesis that domesticated camelids occurred in prehispanic, southern Mendoza through analysis of ancient DNA. We generated whole mitochondrial genome datasets from 41 samples from southern Mendoza late Holocene archaeological sites, located between 450 and 3400 meters above sea level (masl). All camelid samples from those sites were identified as guanaco; thus, we have no evidence to support the hypothesis that the domestic llama occurred in prehispanic southern Mendoza.

RevDate: 2020-11-05

Skelly E, Johnson NW, Kapellas K, et al (2020)

Response of Salivary Microbiota to Caries Preventive Treatment in Aboriginal and Torres Strait Islander Children.

Journal of oral microbiology, 12(1):1830623 pii:1830623.

A once-annual caries preventive (Intervention) treatment was offered to Aboriginal and Torres Strait Islander schoolchildren-a population with disproportionately poorer oral health than non-Indigenous Australian children-in the Northern Peninsula Area (NPA) of Far North Queensland (FNQ), which significantly improved their oral health. Here, we examine the salivary microbiota of these children (mean age = 10 ± 2.96 years; n = 103), reconstructing the bacterial community composition with high-throughput sequencing of the V4 region of bacterial 16S rRNA gene. Microbial communities of children who received the Intervention had lower taxonomic diversity than those who did not receive treatment (Shannon, p < 0.05). Moreover, the Intervention resulted in further decreased microbial diversity in children with active carious lesions existing at the time of saliva collection. Microbial species associated with caries were detected; Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus gasseri, Prevotella multisaccharivorax, Parascardovia denticolens, and Mitsuokella HMT 131 were significantly increased (p < 0.05) in children with severe caries, especially in children who did not receive the Intervention. These insights into microbial associations and community differences prompt future considerations to the mechanisms behind caries-preventive therapy induced change; important for understanding the long-term implications of like treatment to improve oral health disparities within Australia. Trial registration: ANZCTR, ACTRN12615000693527. Registered 3 July 2015, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368750&isReview=true.

RevDate: 2020-11-04
CmpDate: 2020-11-04

Ottoni C, Guellil M, Ozga AT, et al (2019)

Metagenomic analysis of dental calculus in ancient Egyptian baboons.

Scientific reports, 9(1):19637.

Dental calculus, or mineralized plaque, represents a record of ancient biomolecules and food residues. Recently, ancient metagenomics made it possible to unlock the wealth of microbial and dietary information of dental calculus to reconstruct oral microbiomes and lifestyle of humans from the past. Although most studies have so far focused on ancient humans, dental calculus is known to form in a wide range of animals, potentially informing on how human-animal interactions changed the animals' oral ecology. Here, we characterise the oral microbiome of six ancient Egyptian baboons held in captivity during the late Pharaonic era (9th-6th centuries BC) and of two historical baboons from a zoo via shotgun metagenomics. We demonstrate that these captive baboons possessed a distinctive oral microbiome when compared to ancient and modern humans, Neanderthals and a wild chimpanzee. These results may reflect the omnivorous dietary behaviour of baboons, even though health, food provisioning and other factors associated with human management, may have changed the baboons' oral microbiome. We anticipate our study to be a starting point for more extensive studies on ancient animal oral microbiomes to examine the extent to which domestication and human management in the past affected the diet, health and lifestyle of target animals.

RevDate: 2020-09-16
CmpDate: 2020-08-04

Furtwängler A, Rohrlach AB, Lamnidis TC, et al (2020)

Ancient genomes reveal social and genetic structure of Late Neolithic Switzerland.

Nature communications, 11(1):1915 pii:10.1038/s41467-020-15560-x.

Genetic studies of Neolithic and Bronze Age skeletons from Europe have provided evidence for strong population genetic changes at the beginning and the end of the Neolithic period. To further understand the implications of these in Southern Central Europe, we analyze 96 ancient genomes from Switzerland, Southern Germany, and the Alsace region in France, covering the Middle/Late Neolithic to Early Bronze Age. Similar to previously described genetic changes in other parts of Europe from the early 3rd millennium BCE, we detect an arrival of ancestry related to Late Neolithic pastoralists from the Pontic-Caspian steppe in Switzerland as early as 2860-2460 calBCE. Our analyses suggest that this genetic turnover was a complex process lasting almost 1000 years and involved highly genetically structured populations in this region.

RevDate: 2020-11-03

Saag L (2020)

Human Genetics: Lactase Persistence in a Battlefield.

Current biology : CB, 30(21):R1311-R1313.

Lactase persistence is a common genetic trait in Europeans and other pastoralists. New ancient DNA evidence from a Bronze Age battlefield indicates that selection for lactase persistence was strong and on-going in the last 3,000 years.

RevDate: 2020-11-03

Lall GM, Larmuseau MHD, Wetton JH, et al (2020)

Subdividing Y-chromosome haplogroup R1a1 reveals Norse Viking dispersal lineages in Britain.

European journal of human genetics : EJHG pii:10.1038/s41431-020-00747-z [Epub ahead of print].

The influence of Viking-Age migrants to the British Isles is obvious in archaeological and place-names evidence, but their demographic impact has been unclear. Autosomal genetic analyses support Norse Viking contributions to parts of Britain, but show no signal corresponding to the Danelaw, the region under Scandinavian administrative control from the ninth to eleventh centuries. Y-chromosome haplogroup R1a1 has been considered as a possible marker for Viking migrations because of its high frequency in peninsular Scandinavia (Norway and Sweden). Here we select ten Y-SNPs to discriminate informatively among hg R1a1 sub-haplogroups in Europe, analyse these in 619 hg R1a1 Y chromosomes including 163 from the British Isles, and also type 23 short-tandem repeats (Y-STRs) to assess internal diversity. We find three specifically Western-European sub-haplogroups, two of which predominate in Norway and Sweden, and are also found in Britain; star-like features in the STR networks of these lineages indicate histories of expansion. We ask whether geographical distributions of hg R1a1 overall, and of the two sub-lineages in particular, correlate with regions of Scandinavian influence within Britain. Neither shows any frequency difference between regions that have higher (≥10%) or lower autosomal contributions from Norway and Sweden, but both are significantly overrepresented in the region corresponding to the Danelaw. These differences between autosomal and Y-chromosomal histories suggest either male-specific contribution, or the influence of patrilocality. Comparison of modern DNA with recently available ancient DNA data supports the interpretation that two sub-lineages of hg R1a1 spread with the Vikings from peninsular Scandinavia.

RevDate: 2020-11-02

Furtwängler A, Neukamm J, Böhme L, et al (2020)

Comparison of target enrichment strategies for ancient pathogen DNA.

BioTechniques [Epub ahead of print].

In ancient DNA research, the degraded nature of the samples generally results in poor yields of highly fragmented DNA; targeted DNA enrichment is thus required to maximize research outcomes. The three commonly used methods - array-based hybridization capture and in-solution capture using either RNA or DNA baits - have different characteristics that may influence the capture efficiency, specificity and reproducibility. Here we compare their performance in enriching pathogen DNA of Mycobacterium leprae and Treponema pallidum from 11 ancient and 19 modern samples. We find that in-solution approaches are the most effective method in ancient and modern samples of both pathogens and that RNA baits usually perform better than DNA baits.

RevDate: 2020-11-02

Hao S, Han K, Meng L, et al (2020)

African Arowana Genome Provides Insights on Ancient Teleost Evolution.

iScience, 23(11):101662 pii:S2589-0042(20)30854-3.

Osteoglossiformes is a basal clade of teleost, evolving since the Jurassic period. The genomes of Osteoglossiformes species would shed light on the evolution and adaptation of teleost. Here, we established a chromosome-level genome of African arowana. Together with the genomes of pirarucu and Asian arowana, we found that they diverged at ∼106.1 million years ago (MYA) and ∼59.2 MYA, respectively, which are coincident with continental separation. Interestingly, we identified a dynamic genome evolution characterized by a fast evolutionary rate and a high pseudogenization rate in African arowana and pirarucu. Additionally, more transposable elements were found in Asian arowana which confer more gene duplications. Moreover, we found the contraction of olfactory receptor and the expansion of UGT in African arowana might be related to its transformation from carnivore to be omnivore. Taken together, we provided valuable genomic resource of Osteoglossidae and revealed the correlation of biogeography and teleost evolution.

RevDate: 2020-10-30

Ramos-Madrigal J, Sinding MS, Carøe C, et al (2020)

Genomes of Pleistocene Siberian Wolves Uncover Multiple Extinct Wolf Lineages.

Current biology : CB pii:S0960-9822(20)31506-2 [Epub ahead of print].

Extant Canis lupus genetic diversity can be grouped into three phylogenetically distinct clades: Eurasian and American wolves and domestic dogs.1 Genetic studies have suggested these groups trace their origins to a wolf population that expanded during the last glacial maximum (LGM)1-3 and replaced local wolf populations.4 Moreover, ancient genomes from the Yana basin and the Taimyr peninsula provided evidence of at least one extinct wolf lineage that dwelled in Siberia during the Pleistocene.35 Previous studies have suggested that Pleistocene Siberian canids can be classified into two groups based on cranial morphology. Wolves in the first group are most similar to present-day populations, although those in the second group possess intermediate features between dogs and wolves.67 However, whether this morphological classification represents distinct genetic groups remains unknown. To investigate this question and the relationships between Pleistocene canids, present-day wolves, and dogs, we resequenced the genomes of four Pleistocene canids from Northeast Siberia dated between >50 and 14 ka old, including samples from the two morphological categories. We found these specimens cluster with the two previously sequenced Pleistocene wolves, which are genetically more similar to Eurasian wolves. Our results show that, though the four specimens represent extinct wolf lineages, they do not form a monophyletic group. Instead, each Pleistocene Siberian canid branched off the lineage that gave rise to present-day wolves and dogs. Finally, our results suggest the two previously described morphological groups could represent independent lineages similarly related to present-day wolves and dogs.

RevDate: 2020-10-30

Hui R, D'Atanasio E, Cassidy LM, et al (2020)

Evaluating genotype imputation pipeline for ultra-low coverage ancient genomes.

Scientific reports, 10(1):18542 pii:10.1038/s41598-020-75387-w.

Although ancient DNA data have become increasingly more important in studies about past populations, it is often not feasible or practical to obtain high coverage genomes from poorly preserved samples. While methods of accurate genotype imputation from > 1 × coverage data have recently become a routine, a large proportion of ancient samples remain unusable for downstream analyses due to their low coverage. Here, we evaluate a two-step pipeline for the imputation of common variants in ancient genomes at 0.05-1 × coverage. We use the genotype likelihood input mode in Beagle and filter for confident genotypes as the input to impute missing genotypes. This procedure, when tested on ancient genomes, outperforms a single-step imputation from genotype likelihoods, suggesting that current genotype callers do not fully account for errors in ancient sequences and additional quality controls can be beneficial. We compared the effect of various genotype likelihood calling methods, post-calling, pre-imputation and post-imputation filters, different reference panels, as well as different imputation tools. In a Neolithic Hungarian genome, we obtain ~ 90% imputation accuracy for heterozygous common variants at coverage 0.05 × and > 97% accuracy at coverage 0.5 ×. We show that imputation can mitigate, though not eliminate reference bias in ultra-low coverage ancient genomes.

RevDate: 2020-10-30

Keyser C (2017)

Virus and ancient DNA: back to the future.

Virologie (Montrouge, France), 21(6):247-254.

Paleovirology, the study of ancient viruses, is a recent scientific development. It belongs to the domain of ancient DNA studies, paleogenetics. The analytical power of this discipline, that has many applications, is nevertheless limited by the poor conservation of DNA (and RNA) found in fossils and the subsequent methodological problems (amplification issues, post-mortem lesions, contaminations). These issues must be addressed in order to exploit the full potential of preserved nucleic acids within ancient remains. Once these difficulties have been overcome, it becomes possible to characterize ancient viruses and particular steps of their evolution or even adaptation to their hosts. Shedding light on key aspects of past epidemics allows for a better comprehension of present situations and for the anticipation of future situations where viral pathogens emerge or re-emerge. The examples described in this article illustrate these facts.

RevDate: 2020-10-27

Parker C, Rohrlach AB, Friederich S, et al (2020)

A systematic investigation of human DNA preservation in medieval skeletons.

Scientific reports, 10(1):18225 pii:10.1038/s41598-020-75163-w.

Ancient DNA (aDNA) analyses necessitate the destructive sampling of archaeological material. Currently, the cochlea, part of the osseous inner ear located inside the petrous pyramid, is the most sought after skeletal element for molecular analyses of ancient humans as it has been shown to yield high amounts of endogenous DNA. However, destructive sampling of the petrous pyramid may not always be possible, particularly in cases where preservation of skeletal morphology is of top priority. To investigate alternatives, we present a survey of human aDNA preservation for each of ten skeletal elements in a skeletal collection from Medieval Germany. Through comparison of human DNA content and quality we confirm best performance of the petrous pyramid and identify seven additional sampling locations across four skeletal elements that yield adequate aDNA for most applications in human palaeogenetics. Our study provides a better perspective on DNA preservation across the human skeleton and takes a further step toward the more responsible use of ancient materials in human aDNA studies.

RevDate: 2020-10-27

Guellil M, Kersten O, Namouchi A, et al (2020)

A genomic and historical synthesis of plague in 18th century Eurasia.

Proceedings of the National Academy of Sciences of the United States of America pii:2009677117 [Epub ahead of print].

Plague continued to afflict Europe for more than five centuries after the Black Death. Yet, by the 17th century, the dynamics of plague had changed, leading to its slow decline in Western Europe over the subsequent 200 y, a period for which only one genome was previously available. Using a multidisciplinary approach, combining genomic and historical data, we assembled Y. pestis genomes from nine individuals covering four Eurasian sites and placed them into an historical context within the established phylogeny. CHE1 (Chechnya, Russia, 18th century) is now the latest Second Plague Pandemic genome and the first non-European sample in the post-Black Death lineage. Its placement in the phylogeny and our synthesis point toward the existence of an extra-European reservoir feeding plague into Western Europe in multiple waves. By considering socioeconomic, ecological, and climatic factors we highlight the importance of a noneurocentric approach for the discussion on Second Plague Pandemic dynamics in Europe.

RevDate: 2020-10-27
CmpDate: 2020-10-27

Toncheva D, Serbezov D, Karachanak-Yankova S, et al (2020)

Ancient mitochondrial DNA pathogenic variants putatively associated with mitochondrial disease.

PloS one, 15(9):e0233666.

Mitochondrial DNA variants associated with diseases are widely studied in contemporary populations, but their prevalence has not yet been investigated in ancient populations. The publicly available AmtDB database contains 1443 ancient mtDNA Eurasian genomes from different periods. The objective of this study was to use this data to establish the presence of pathogenic mtDNA variants putatively associated with mitochondrial diseases in ancient populations. The clinical significance, pathogenicity prediction and contemporary frequency of mtDNA variants were determined using online platforms. The analyzed ancient mtDNAs contain six variants designated as being "confirmed pathogenic" in modern patients. The oldest of these, m.7510T>C in the MT-TS1 gene, was found in a sample from the Neolithic period, dated 5800-5400 BCE. All six have well established clinical association, and their pathogenic effect is corroborated by very low population frequencies in contemporary populations. Analysis of the geographic location of the ancient samples, contemporary epidemiological trends and probable haplogroup association indicate diverse spatiotemporal dynamics of these variants. The dynamics in the prevalence and distribution is conceivably result of de novo mutations or human migrations and subsequent evolutionary processes. In addition, ten variants designated as possibly or likely pathogenic were found, but the clinical effect of these is not yet well established and further research is warranted. All detected mutations putatively associated with mitochondrial disease in ancient mtDNA samples are in tRNA coding genes. Most of these mutations are in a mt-tRNA type (Model 2) that is characterized by loss of D-loop/T-loop interaction. Exposing pathogenic variants in ancient human populations expands our understanding of their origin and prevalence dynamics.

RevDate: 2020-10-20

Earn DJD, Ma J, Poinar H, et al (2020)

Acceleration of plague outbreaks in the second pandemic.

Proceedings of the National Academy of Sciences of the United States of America pii:2004904117 [Epub ahead of print].

Historical records reveal the temporal patterns of a sequence of plague epidemics in London, United Kingdom, from the 14th to 17th centuries. Analysis of these records shows that later epidemics spread significantly faster ("accelerated"). Between the Black Death of 1348 and the later epidemics that culminated with the Great Plague of 1665, we estimate that the epidemic growth rate increased fourfold. Currently available data do not provide enough information to infer the mode of plague transmission in any given epidemic; nevertheless, order-of-magnitude estimates of epidemic parameters suggest that the observed slow growth rates in the 14th century are inconsistent with direct (pneumonic) transmission. We discuss the potential roles of demographic and ecological factors, such as climate change or human or rat population density, in driving the observed acceleration.

RevDate: 2020-10-20

Chen N, Ren L, Du L, et al (2020)

Ancient genomes reveal tropical bovid species in the Tibetan Plateau contributed to the prevalence of hunting game until the late Neolithic.

Proceedings of the National Academy of Sciences of the United States of America pii:2011696117 [Epub ahead of print].

Local wild bovids have been determined to be important prey on the northeastern Tibetan Plateau (NETP), where hunting game was a major subsistence strategy until the late Neolithic, when farming lifestyles dominated in the neighboring Loess Plateau. However, the species affiliation and population ecology of these prehistoric wild bovids in the prehistoric NETP remain unknown. Ancient DNA (aDNA) analysis is highly informative in decoding this puzzle. Here, we applied aDNA analysis to fragmented bovid and rhinoceros specimens dating ∼5,200 y B.P. from the Neolithic site of Shannashuzha located in the marginal area of the NETP. Utilizing both whole genomes and mitochondrial DNA, our results demonstrate that the range of the present-day tropical gaur (Bos gaurus) extended as far north as the margins of the NETP during the late Neolithic from ∼29°N to ∼34°N. Furthermore, comparative analysis with zooarchaeological and paleoclimatic evidence indicated that a high summer temperature in the late Neolithic might have facilitated the northward expansion of tropical animals (at least gaur and Sumatran-like rhinoceros) to the NETP. This enriched the diversity of wildlife, thus providing abundant hunting resources for humans and facilitating the exploration of the Tibetan Plateau as one of the last habitats for hunting game in East Asia.

RevDate: 2020-10-16

Barnett R, Westbury MV, Sandoval-Velasco M, et al (2020)

Genomic Adaptations and Evolutionary History of the Extinct Scimitar-Toothed Cat, Homotherium latidens.

Current biology : CB pii:S0960-9822(20)31421-4 [Epub ahead of print].

Homotherium was a genus of large-bodied scimitar-toothed cats, morphologically distinct from any extant felid species, that went extinct at the end of the Pleistocene [1-4]. They possessed large, saber-form serrated canine teeth, powerful forelimbs, a sloping back, and an enlarged optic bulb, all of which were key characteristics for predation on Pleistocene megafauna [5]. Previous mitochondrial DNA phylogenies suggested that it was a highly divergent sister lineage to all extant cat species [6-8]. However, mitochondrial phylogenies can be misled by hybridization [9], incomplete lineage sorting (ILS), or sex-biased dispersal patterns [10], which might be especially relevant for Homotherium since widespread mito-nuclear discrepancies have been uncovered in modern cats [10]. To examine the evolutionary history of Homotherium, we generated a ∼7x nuclear genome and a ∼38x exome from H. latidens using shotgun and target-capture sequencing approaches. Phylogenetic analyses reveal Homotherium as highly divergent (∼22.5 Ma) from living cat species, with no detectable signs of gene flow. Comparative genomic analyses found signatures of positive selection in several genes, including those involved in vision, cognitive function, and energy consumption, putatively consistent with diurnal activity, well-developed social behavior, and cursorial hunting [5]. Finally, we uncover relatively high levels of genetic diversity, suggesting that Homotherium may have been more abundant than the limited fossil record suggests [3, 4, 11-14]. Our findings complement and extend previous inferences from both the fossil record and initial molecular studies, enhancing our understanding of the evolution and ecology of this remarkable lineage.

RevDate: 2020-10-16

Lipson M, Spriggs M, Valentin F, et al (2020)

Three Phases of Ancient Migration Shaped the Ancestry of Human Populations in Vanuatu.

Current biology : CB pii:S0960-9822(20)31366-X [Epub ahead of print].

The archipelago of Vanuatu has been at the crossroads of human population movements in the Pacific for the past three millennia. To help address several open questions regarding the history of these movements, we generated genome-wide data for 11 ancient individuals from the island of Efate dating from its earliest settlement to the recent past, including five associated with the Chief Roi Mata's Domain World Heritage Area, and analyzed them in conjunction with 34 published ancient individuals from Vanuatu and elsewhere in Oceania, as well as present-day populations. Our results outline three distinct periods of population transformations. First, the four earliest individuals, from the Lapita-period site of Teouma, are concordant with eight previously described Lapita-associated individuals from Vanuatu and Tonga in having almost all of their ancestry from a "First Remote Oceanian" source related to East and Southeast Asians. Second, both the Papuan ancestry predominating in Vanuatu for the past 2,500 years and the smaller component of Papuan ancestry found in Polynesians can be modeled as deriving from a single source most likely originating in New Britain, suggesting that the movement of people carrying this ancestry to Remote Oceania closely followed that of the First Remote Oceanians in time and space. Third, the Chief Roi Mata's Domain individuals descend from a mixture of Vanuatu- and Polynesian-derived ancestry and are related to Polynesian-influenced communities today in central, but not southern, Vanuatu, demonstrating Polynesian genetic input in multiple groups with independent histories.

RevDate: 2020-10-15

Gad YZ, Hassan NA, Mousa DM, et al (2020)

Insights from ancient DNA analysis of Egyptian human mummies: clues to disease and kinship.

Human molecular genetics pii:5924364 [Epub ahead of print].

The molecular Egyptology field started in the mid-eighties with the first publication on the ancient DNA (aDNA) analysis of an Egyptian mummy. Egypt has been a major interest for historians, archaeologists, laymen as well as scientists. The aDNA research on Egyptian biological remains has been fueled by their abundance and relatively well-preserved states through artificial mummification and by the advanced analytical techniques. Early doubts of aDNA integrity within the Egyptian mummies and data authenticity were later abated with studies proving successfully authenticated aDNA retrieval. The current review tries to recapitulate the published studies presenting paleogenomic evidence of disease diagnosis and kinship establishment for the Egyptian human remains. Regarding disease diagnosis, the prevailing literature was on paleogenomic evidence of infectious diseases in the human remains. A series of reports presented evidence for the presence of tuberculosis and/or malaria. In addition, there were solitary reports of the presence of leprosy, diphtheria, bacteremia, toxoplasmosis, schistosomiasis and leishmaniasis. On the contrary, paleogenomic evidence of the presence of rare diseases was quite scarce and mentioned only in two articles. On the other hand, kinship analysis of Egyptian human remains, including that of Tutankhamen, was done using both mitochondrial DNA sequences and nuclear DNA markers, to establish family relationships in four studies. It is clear that the field of molecular Egyptology is still a largely unexplored territory. Nevertheless, the paleogenomic investigation of Egyptian remains could make significant contributions to biomedical sciences [e.g. elucidation of co-evolution of human host-microbe interrelationship] as well as to evidence-based archeology.

RevDate: 2020-10-15

Lasa-Fernandez H, Mosqueira-Martín L, Alzualde A, et al (2020)

A genotyping method combining primer competition PCR with HRM analysis to identify point mutations in Duchenne animal models.

Scientific reports, 10(1):17224 pii:10.1038/s41598-020-74173-y.

Dystrophin-null sapje zebrafish is an excellent model for better understanding the pathological mechanisms underlying Duchenne muscular dystrophy, and it has recently arisen as a powerful tool for high-throughput screening of therapeutic candidates for this disease. While dystrophic phenotype in sapje larvae can be easily detected by birefringence, zebrafish genotyping is necessary for drug screening experiments, where the potential rescue of larvae phenotype is the primary outcome. Genotyping is also desirable during colony husbandry since heterozygous progenitors need to be selected. Currently, sapje zebrafish are genotyped through techniques involving sequencing or multi-step PCR, which are often costly, tedious, or require special equipment. Here we report a simple, precise, cost-effective, and versatile PCR genotyping method based on primer competition. Genotypes can be resolved by standard agarose gel electrophoresis and high-resolution melt assay, the latter being especially useful for genotyping a large number of samples. Our approach has shown high sensitivity, specificity, and reproducibility in detecting the A/T point mutation in sapje zebrafish and the C/T mutation in the mdx mouse model of Duchenne. Hence, this method can be applied to other single nucleotide substitutions and may be further optimized to detect small insertions and deletions. Given its robust performance with crude DNA extracts, our strategy may be particularly well-suited for detecting single nucleotide variants in poor-quality samples such as ancient DNA or DNA from formalin-fixed, paraffin-embedded material.

RevDate: 2020-10-13

Drosou K, Collin TC, Freeman PJ, et al (2020)

The first reported case of the rare mitochondrial haplotype H4a1 in ancient Egypt.

Scientific reports, 10(1):17037 pii:10.1038/s41598-020-74114-9.

Takabuti, was a female who lived in ancient Egypt during the 25th Dynasty, c.660 BCE. Her mummified remains were brought to Belfast, Northern Ireland, in 1834 and are currently displayed in the Ulster Museum. To gain insight into Takabuti's ancestry, we used deep sampling of vertebral bone, under X-ray control, to obtain non-contaminated bone tissue from which we extracted ancient DNA (aDNA) using established protocols. We targeted the maternally inherited mitochondrial DNA (mtDNA), known to be highly informative for human ancestry, and identified 38 single nucleotide variants using next generation sequencing. The specific combination of these SNVs suggests that Takabuti belonged to mitochondrial haplogroup H4a1. Neither H4 nor H4a1 have been reported in ancient Egyptian samples, prior to this study. The modern distribution of H4a1 is rare and sporadic and has been identified in areas including the Canary Islands, southern Iberia and the Lebanon. H4a1 has also been reported in ancient samples from Bell Beaker and Unetice contexts in Germany, as well as Bronze Age Bulgaria. We believe that this is an important finding because first, it adds to the depth of knowledge about the distribution of the H4a1 haplogroup in existing mtDNA, thus creating a baseline for future occurrences of this haplogroup in ancient Egyptian remains. Second, it is of great importance for archaeological sciences, since a predominantly European haplogroup has been identified in an Egyptian individual in Southern Egypt, prior to the Roman and Greek influx (332BCE).

RevDate: 2020-10-09

Woods R, Barnes I, Brace S, et al (2020)

Ancient DNA suggests single colonisation and within-archipelago diversification of Caribbean caviomorph rodents.

Molecular biology and evolution pii:5920246 [Epub ahead of print].

Reconstructing the evolutionary history of island biotas is complicated by unusual morphological evolution in insular environments. However, past human-caused extinctions limit the use of molecular analyses to determine origins and affinities of enigmatic island taxa. The Caribbean formerly contained a morphologically diverse assemblage of caviomorph rodents (33 species in 19 genera), ranging from ∼0.1-200 kg and traditionally classified into three higher-order taxa (Capromyidae/Capromyinae, Heteropsomyinae, Heptaxodontidae). Few species survive today, and the evolutionary affinities of living and extinct Caribbean caviomorphs to each other and to mainland taxa are unclear: are they monophyletic, polyphyletic, or paraphyletic? We use ancient DNA techniques to present the first genetic data for extinct heteropsomyines and heptaxodontids, as well as for several extinct capromyids, and demonstrate through analysis of mitogenomic and nuclear datasets that all sampled Caribbean caviomorphs represent a well-supported monophyletic group. The remarkable morphological and ecological variation observed across living and extinct caviomorphs from Cuba, Hispaniola, Jamaica, Puerto Rico, and other islands was generated through within-archipelago evolutionary radiation following a single Early Miocene overwater colonisation. This evolutionary pattern contrasts with the origination of diversity in many other Caribbean groups. All living and extinct Caribbean caviomorphs comprise a single biologically remarkable subfamily (Capromyinae) within the morphologically conservative living Neotropical family Echimyidae. Caribbean caviomorphs represent an important new example of insular mammalian adaptive radiation, where taxa retaining "ancestral-type" characteristics coexisted alongside taxa occupying novel island niches. Diversification was associated with the greatest insular body mass increase recorded in rodents, and possibly the greatest for any mammal lineage.

RevDate: 2020-10-08

Rao H, Yang Y, Liu J, et al (2020)

Palaeoproteomic analysis of Pleistocene cave hyenas from east Asia.

Scientific reports, 10(1):16674 pii:10.1038/s41598-020-73542-x.

The spotted hyena (Crocuta crocuta) is the only extant species of the genus Crocuta, which once occupied a much wider range during the Pliocene and Pleistocene. However, its origin and evolutionary history is somewhat contentious due to discordances between morphological, nuclear, and mitochondrial data. Due to the limited molecular data from east Asian Crocuta, also known as cave hyena, and the difficulty of extracting ancient DNA from this area, here we present proteomic analysis of cave hyenas from three locations in northern China. This marks the first proteomic data generated from cave hyenas, adding new molecular data to the east Asian populations. Phylogenetic analysis based on these protein sequences reveals two different groups of cave hyenas in east Asia, one of which could not be distinguished from modern spotted hyenas from northern Africa, tentatively the result of previously suggested gene flow between these lineages. With developments of instrumentation and analytical methods, proteomics holds promising potential for molecular phylogenetic reconstructions of ancient fauna previously thought to be unreachable using ancient DNA.

RevDate: 2020-10-06

Duchêne S, Ho SYW, Carmichael AG, et al (2020)

The Recovery, Interpretation and Use of Ancient Pathogen Genomes.

Current biology : CB, 30(19):R1215-R1231.

The ability to sequence genomes from ancient biological material has provided a rich source of information for evolutionary biology and engaged considerable public interest. Although most studies of ancient genomes have focused on vertebrates, particularly archaic humans, newer technologies allow the capture of microbial pathogens and microbiomes from ancient and historical human and non-human remains. This coming of age has been made possible by techniques that allow the preferential capture and amplification of discrete genomes from a background of predominantly host and environmental DNA. There are now near-complete ancient genome sequences for three pathogens of considerable historical interest - pre-modern bubonic plague (Yersinia pestis), smallpox (Variola virus) and cholera (Vibrio cholerae) - and for three equally important endemic human disease agents - Mycobacterium tuberculosis (tuberculosis), Mycobacterium leprae (leprosy) and Treponema pallidum pallidum (syphilis). Genomic data from these pathogens have extended earlier work by paleopathologists. There have been efforts to sequence the genomes of additional ancient pathogens, with the potential to broaden our understanding of the infectious disease burden common to past populations from the Bronze Age to the early 20th century. In this review we describe the state-of-the-art of this rapidly developing field, highlight the contributions of ancient pathogen genomics to multidisciplinary endeavors and describe some of the limitations in resolving questions about the emergence and long-term evolution of pathogens.

RevDate: 2020-10-06

Fleskes RE, Ofunniyin AA, Gilmore JK, et al (2020)

Ancestry, health, and lived experiences of enslaved Africans in 18th century Charleston: An osteobiographical analysis.

American journal of physical anthropology [Epub ahead of print].

OBJECTIVES: In 2013, the burials of 36 individuals of putative African ancestry were discovered during renovation of the Gaillard Center in downtown Charleston, South Carolina. The Charleston community facilitated a bioarchaeological and mitogenomic study to gain insights into the lives of these unknown persons, referred to as the Anson Street Ancestors, including their ancestry, health, and lived experiences in the 18th century.

METHODS: Metric and morphological assessments of skeletal and dental characteristics were recorded, and enamel and cortical bone strontium stable isotope values generated. Whole mitochondrial genomes were sequenced and analyzed.

RESULTS: Osteological analysis identified adults, both females and males, and subadults at the site, and estimated African ancestry for most individuals. Skeletal trauma and pathology were infrequent, but many individuals exhibited dental decay and abscesses. Strontium isotope data suggested these individuals mostly originated in Charleston or sub-Saharan Africa, with many being long-term residents of Charleston. Nearly all had mitochondrial lineages belonging to African haplogroups (L0-L3, H1cb1a), with two individuals sharing the same L3e2a haplotype, while one had a Native American A2 mtDNA.

DISCUSSION: This study generated detailed osteobiographies of the Anson Street Ancestors, who were likely of enslaved status. Our results indicate that the Ancestors have diverse maternal African ancestries and are largely unrelated, with most being born locally. These details reveal the demographic impact of the trans-Atlantic slave trade. Our analysis further illuminates the lived experiences of individuals buried at Anson Street, and expands our understanding of 18th century African history in Charleston.

RevDate: 2020-10-05

Ferrari G, Neukamm J, Baalsrud HT, et al (2020)

Variola virus genome sequenced from an eighteenth-century museum specimen supports the recent origin of smallpox.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190572.

Smallpox, caused by the variola virus (VARV), was a highly virulent disease with high mortality rates causing a major threat for global human health until its successful eradication in 1980. Despite previously published historic and modern VARV genomes, its past dissemination and diversity remain debated. To understand the evolutionary history of VARV with respect to historic and modern VARV genetic variation in Europe, we sequenced a VARV genome from a well-described eighteenth-century case from England (specimen P328). In our phylogenetic analysis, the new genome falls between the modern strains and another historic strain from Lithuania, supporting previous claims of larger diversity in early modern Europe compared to the twentieth century. Our analyses also resolve a previous controversy regarding the common ancestor between modern and historic strains by confirming a later date around the seventeenth century. Overall, our results point to the benefit of historic genomes for better resolution of past VARV diversity and highlight the value of such historic genomes from around the world to further understand the evolutionary history of smallpox as well as related diseases. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-05

Flammer PG, AL Smith (2020)

Intestinal helminths as a biomolecular complex in archaeological research.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190570.

Enteric helminths are common parasites in many parts of the world and in the past were much more widespread both geographically and socially. Many enteric helminths are relatively long-lived in the human host, often benign or of low pathogenicity while producing large numbers of environmentally resistant eggs voided in the faeces or found associated with individual remains (skeletons and mummies). The combination of helminth characters offers opportunities to the field of historical pathogen research that are quite different to that of some of the more intensively studied high impact pathogens. Historically, a wealth of studies has employed microscopic techniques to diagnose infection using the morphology of the helminth eggs. More recently, various ancient DNA (aDNA) approaches have been applied in the archaeoparasitological context and these are revolutionizing the field, allowing much more specific diagnosis as well as interrogating the epidemiology of helminths. These advances have enhanced the potential for the field to provide unique information on past populations including using diseases to consider many aspects of life (e.g. sanitation, hygiene, diet, culinary practices and other aspects of society). Here, we consider the impact of helminth archaeoparasitology and more specifically the impact and potential for application of aDNA technologies as a part of the archaeologists' toolkit. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-05

Achtman M, Z Zhou (2020)

Metagenomics of the modern and historical human oral microbiome with phylogenetic studies on Streptococcus mutans and Streptococcus sobrinus.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190573.

We have recently developed bioinformatic tools to accurately assign metagenomic sequence reads to microbial taxa: SPARSE for probabilistic, taxonomic classification of sequence reads; EToKi for assembling and polishing genomes from short-read sequences; and GrapeTree, a graphic visualizer of genetic distances between large numbers of genomes. Together, these methods support comparative analyses of genomes from ancient skeletons and modern humans. Here, we illustrate these capabilities with 784 samples from historical dental calculus, modern saliva and modern dental plaque. The analyses revealed 1591 microbial species within the oral microbiome. We anticipated that the oral complexes of Socransky et al., which were defined in 1998, would predominate among taxa whose frequencies differed by source. However, although some species discriminated between sources, we could not confirm the existence of the complexes. The results also illustrate further functionality of our pipelines with two species that are associated with dental caries, Streptococcus mutans and Streptococcus sobrinus. They were rare in historical dental calculus but common in modern plaque, and even more common in saliva. Reconstructed draft genomes of these two species from metagenomic samples in which they were abundant were combined with modern public genomes to provide a detailed overview of their core genomic diversity. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-05

Fotakis AK, Denham SD, Mackie M, et al (2020)

Multi-omic detection of Mycobacterium leprae in archaeological human dental calculus.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190584.

Mineralized dental plaque (calculus) has proven to be an excellent source of ancient biomolecules. Here we present a Mycobacterium leprae genome (6.6-fold), the causative agent of leprosy, recovered via shotgun sequencing of sixteenth-century human dental calculus from an individual from Trondheim, Norway. When phylogenetically placed, this genome falls in branch 3I among the diversity of other contemporary ancient strains from Northern Europe. Moreover, ancient mycobacterial peptides were retrieved via mass spectrometry-based proteomics, further validating the presence of the pathogen. Mycobacterium leprae can readily be detected in the oral cavity and associated mucosal membranes, which likely contributed to it being incorporated into this individual's dental calculus. This individual showed some possible, but not definitive, evidence of skeletal lesions associated with early-stage leprosy. This study is the first known example of successful multi-omics retrieval of M. leprae from archaeological dental calculus. Furthermore, we offer new insights into dental calculus as an alternative sample source to bones or teeth for detecting and molecularly characterizing M. leprae in individuals from the archaeological record. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-05

Morozova I, Kasianov A, Bruskin S, et al (2020)

New ancient Eastern European Yersinia pestis genomes illuminate the dispersal of plague in Europe.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190569.

Yersinia pestis, the causative agent of plague, has been prevalent among humans for at least 5000 years, being accountable for several devastating epidemics in history, including the Black Death. Analyses of the genetic diversity of ancient strains of Y. pestis have shed light on the mechanisms of evolution and the spread of plague in Europe. However, many questions regarding the origins of the pathogen and its long persistence in Europe are still unresolved, especially during the late medieval time period. To address this, we present four newly assembled Y. pestis genomes from Eastern Europe (Poland and Southern Russia), dating from the fifteenth to eighteenth century AD. The analysis of polymorphisms in these genomes and their phylogenetic relationships with other ancient and modern Y. pestis strains may suggest several independent introductions of plague into Eastern Europe or its persistence in different reservoirs. Furthermore, with the reconstruction of a partial Y. pestis genome from rat skeletal remains found in a Polish ossuary, we were able to identify a potential animal reservoir in late medieval Europe. Overall, our results add new information concerning Y. pestis transmission and its evolutionary history in Eastern Europe. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-05

Eisenhofer R, Kanzawa-Kiriyama H, Shinoda KI, et al (2020)

Investigating the demographic history of Japan using ancient oral microbiota.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 375(1812):20190578.

While microbial communities in the human body (microbiota) are now commonly associated with health and disease in industrialised populations, we know very little about how these communities co-evolved and changed with humans throughout history and deep prehistory. We can now examine these communities by sequencing ancient DNA preserved within calcified dental plaque (calculus), providing insights into the origins of disease and their links to human history. Here, we examine ancient DNA preserved within dental calculus samples and their associations with two major cultural periods in Japan: the Jomon period hunter-gatherers approximately 3000 years before present (BP) and the Edo period agriculturalists 400-150 BP. We investigate how human oral microbiomes have changed in Japan through time and explore the presence of microorganisms associated with oral diseases (e.g. periodontal disease, dental caries) in ancient Japanese populations. Finally, we explore oral microbial strain diversity and its potential links to ancient demography in ancient Japan by performing phylogenomic analysis of a widely conserved oral species-Anaerolineaceae oral taxon 439. This research represents, to our knowledge, the first study of ancient oral microbiomes from Japan and demonstrates that the analysis of ancient dental calculus can provide key information about the origin of non-infectious disease and its deep roots with human demography. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

RevDate: 2020-10-02

Brealey JC, Leitão HG, van der Valk T, et al (2020)

Dental Calculus as a Tool to Study the Evolution of the Mammalian Oral Microbiome.

Molecular biology and evolution, 37(10):3003-3022.

Dental calculus, the calcified form of the mammalian oral microbial plaque biofilm, is a rich source of oral microbiome, host, and dietary biomolecules and is well preserved in museum and archaeological specimens. Despite its wide presence in mammals, to date, dental calculus has primarily been used to study primate microbiome evolution. We establish dental calculus as a valuable tool for the study of nonhuman host microbiome evolution, by using shotgun metagenomics to characterize the taxonomic and functional composition of the oral microbiome in species as diverse as gorillas, bears, and reindeer. We detect oral pathogens in individuals with evidence of oral disease, assemble near-complete bacterial genomes from historical specimens, characterize antibiotic resistance genes, reconstruct components of the host diet, and recover host genetic profiles. Our work demonstrates that metagenomic analyses of dental calculus can be performed on a diverse range of mammalian species, which will allow the study of oral microbiome and pathogen evolution from a comparative perspective. As dental calculus is readily preserved through time, it can also facilitate the quantification of the impact of anthropogenic changes on wildlife and the environment.

RevDate: 2020-10-03

Horsburgh KA, AL Gosling (2020)

Systematic Ancient DNA Species Identification Fails to Find Late Holocene Domesticated Cattle in Southern Africa.

Biology, 9(10): pii:biology9100316.

Establishing robust temporal control of the arrival of domesticated stock and the associated husbandry skills and lifeways in Southern Africa remains frustrated by the osteological similarities between domestic stock and wild endemic fauna. We report the results of a systematic ancient DNA survey of appropriately sized bovid remains from Later Stone Age deposits in four South African archaeological sites. We show that none of the tested remains originated in domesticated cattle. The precise date of arrival of domestic cattle in the region awaits further study, although we also report new radiocarbon determinations which further refine the local chronology.

RevDate: 2020-10-02

Robène I, Maillot-Lebon V, Chabirand A, et al (2020)

Development and comparative validation of genomic-driven PCR-based assays to detect Xanthomonas citri pv. citri in citrus plants.

BMC microbiology, 20(1):296 pii:10.1186/s12866-020-01972-8.

BACKGROUND: Asiatic Citrus Canker, caused by Xanthomonas citri pv. citri, severely impacts citrus production worldwide and hampers international trade. Considerable regulatory procedures have been implemented to prevent the introduction and establishment of X. citri pv. citri into areas where it is not present. The effectiveness of this surveillance largely relies on the availability of specific and sensitive detection protocols. Although several PCR- or real-time PCR-based methods are available, most of them showed analytical specificity issues. Therefore, we developed new conventional and real-time quantitative PCR assays, which target a region identified by comparative genomic analyses, and compared them to existing protocols.

RESULTS: Our assays target the X. citri pv. citri XAC1051 gene that encodes for a putative transmembrane protein. The real-time PCR assay includes an internal plant control (5.8S rDNA) for validating the assay in the absence of target amplification. A receiver-operating characteristic approach was used in order to determine a reliable cycle cut-off for providing accurate qualitative results. Repeatability, reproducibility and transferability between real-time devices were demonstrated for this duplex qPCR assay (XAC1051-2qPCR). When challenged with an extensive collection of target and non-target strains, both assays displayed a high analytical sensitivity and specificity performance: LOD95% = 754 CFU ml- 1 (15 cells per reaction), 100% inclusivity, 97.2% exclusivity for XAC1051-2qPCR; LOD95% = 5234 CFU ml- 1 (105 cells per reaction), 100% exclusivity and inclusivity for the conventional PCR. Both assays can detect the target from naturally infected citrus fruit. Interestingly, XAC1051-2qPCR detected X. citri pv. citri from herbarium citrus samples. The new PCR-based assays displayed enhanced analytical sensitivity and specificity when compared with previously published PCR and real-time qPCR assays.

CONCLUSIONS: We developed new valuable detection assays useful for routine diagnostics and surveillance of X. citri pv. citri in citrus material. Their reliability was evidenced through numerous trials on a wide range of bacterial strains and plant samples. Successful detection of the pathogen was achieved from both artificially and naturally infected plants, as well as from citrus herbarium samples, suggesting that these assays will have positive impact both for future applied and academic research on this bacterium.

RevDate: 2020-09-28

Recht J, Schuenemann VJ, MR Sánchez-Villagra (2020)

Host Diversity and Origin of Zoonoses: The Ancient and the New.

Animals : an open access journal from MDPI, 10(9): pii:ani10091672.

Bacterial, viral, and parasitic zoonotic diseases are transmitted to humans from a wide variety of animal species that act as reservoir hosts for the causative organisms. Zoonoses contribute an estimated 75% of new or reemerging infectious diseases in humans. All groups of mammals have been shown to act as hosts for transmission of different organisms that cause zoonoses, followed in importance by birds; with both wild and domestic species identified as hosts in specific cases. There has been considerable research progress leading to a better understanding of the host range, animal origin, evolution, and transmission of important zoonoses, including those caused by the ingestion of food and products derived from animals. Paleopathology studies of ancient human bone lesions, in combination with ancient DNA analysis of the causative pathogen, have contributed to our understanding of the origin of zoonotic diseases, including brucellosis and mycobacterial zoonoses. However, there are still knowledge gaps and new confirmed and potential hosts are reported locally with some frequency. Both the economic cost and burden of disease of zoonoses are substantial at local and global levels, as reflected by recent coronavirus pandemics that spread rapidly around the world. Evidence-based prevention strategies are currently a global priority increasingly recognized, especially in zoonoses-affected regions.

RevDate: 2020-10-01

Vinueza-Espinosa DC, Santos C, Martínez-Labarga C, et al (2020)

Human DNA Extraction from Highly Degraded Skeletal Remains: How to find a suitable method?.

Electrophoresis [Epub ahead of print].

Retrieving DNA from highly-degraded human skeletal remains is still a challenge due to low concentration and fragmentation which makes it difficult to extract and purify. Recent works showed that silica-based methods allow better DNA recovery and this fact may be attributed to the type of bones and the quality of the preserved tissue. However, more systematic studies are needed to evaluate the efficiency of the different silica-based extraction methods considering the type of bones. The main goal of the present study is to establish the best extraction method and the type of bone that can maximize the recovery of PCR-amplifiable DNA and the subsequent retrieval of mitochondrial and nuclear genetic information. Five individuals were selected from an archaeological site located in Catalonia-Spain dating from 5-11th centuries AD. For each individual, five samples from different skeletal regions were collected: petrous bone, pulp cavity and cementum of tooth, rib and limb bones. Four extraction methods were tested, three silica-based (silica in-suspension, in HE-column and in XS plasma-column) and the classical method based on Phenol-Chloroform. Silica in-suspension method from petrous bone and pulp cavity showed the best results. However, the remains preservation will ultimately be the key to the molecular result success This article is protected by copyright. All rights reserved.

RevDate: 2020-09-30

Nishimura L, Sugimoto R, Inoue J, et al (2020)

Identification of ancient viruses from metagenomic data of the Jomon people.

Journal of human genetics pii:10.1038/s10038-020-00841-6 [Epub ahead of print].

Ancient DNA studies provide genomic information about the origins, population structures, and physical characteristics of ancient humans that cannot be solely examined by archeological studies. The DNAs extracted from ancient human bones, teeth, or tissues are often contaminated with coexisting bacterial and viral genomes that contain DNA from ancient microbes infecting those of ancient humans. Information on ancient viral genomes is useful in making inferences about the viral evolution. Here, we have utilized metagenomic sequencing data from the dental pulp of five Jomon individuals, who lived on the Japanese archipelago more than 3000 years ago; this is to detect ancient viral genomes. We conducted de novo assembly of the non-human reads where we have obtained 277,387 contigs that were longer than 1000 bp. These contigs were subjected to homology searches against a collection of modern viral genome sequences. We were able to detect eleven putative ancient viral genomes. Among them, we reconstructed the complete sequence of the Siphovirus contig89 (CT89) viral genome. The Jomon CT89-like sequence was determined to contain 59 open reading frames, among which five genes known to encode phage proteins were under strong purifying selection. The host of CT89 was predicted to be Schaalia meyeri, a bacterium residing in the human oral cavity. Finally, the CT89 phylogenetic tree showed two clusters, from both of which the Jomon sequence was separated. Our results suggest that metagenomic information from the dental pulp of the Jomon people is essential in retrieving ancient viral genomes used to examine their evolution.

RevDate: 2020-09-28

Peris D, Janssen K, Barthel HJ, et al (2020)

DNA from resin-embedded organisms: Past, present and future.

PloS one, 15(9):e0239521 pii:PONE-D-20-02649.

Past claims have been made for fossil DNA recovery from various organisms (bacteria, plants, insects and mammals, including humans) dating back in time from thousands to several million years BP. However, many of these recoveries, especially those described from million-year-old amber (fossil resin), have faced criticism as being the result of modern environmental contamination and for lack of reproducibility. Using modern genomic techniques, DNA can be obtained with confidence from a variety of substrates (e.g. bones, teeth, gum, museum specimens and fossil insects) of different ages, albeit always less than one million years BP, and results can also be obtained from much older materials using palaeoproteomics. Nevertheless, new attempts to determine if ancient DNA (aDNA) is present in insects preserved in 40 000-year old sub-fossilised resin, the precursor of amber, have been unsuccessful or not well documented. Resin-embedded specimens are therefore regarded as unsuitable for genetic studies. However, we demonstrate here, for the first time, that although a labile molecule, DNA is still present in platypodine beetles (Coleoptera: Curculionidae) embedded in six-year-old and two-year-old resin pieces from Hymenaea verrucosa (Angiospermae: Fabaceae) collected in Madagascar. We describe an optimised method which meets all the requirements and precautions for aDNA experiments for our purpose: to explore the DNA preservation limits in resin. Our objective is far from starting an uncontrolled search for aDNA in amber as it was in the past, but to start resolving basic aspects from the DNA preservation in resin and search from the most modern samples to the ancient ones, step by step. We conclude that it is therefore possible to study genomics from resin-embedded organisms, although the time limits remain to be determined.

RevDate: 2020-09-25

Petr M, Hajdinjak M, Fu Q, et al (2020)

The evolutionary history of Neanderthal and Denisovan Y chromosomes.

Science (New York, N.Y.), 369(6511):1653-1656.

Ancient DNA has provided new insights into many aspects of human history. However, we lack comprehensive studies of the Y chromosomes of Denisovans and Neanderthals because the majority of specimens that have been sequenced to sufficient coverage are female. Sequencing Y chromosomes from two Denisovans and three Neanderthals shows that the Y chromosomes of Denisovans split around 700 thousand years ago from a lineage shared by Neanderthals and modern human Y chromosomes, which diverged from each other around 370 thousand years ago. The phylogenetic relationships of archaic and modern human Y chromosomes differ from the population relationships inferred from the autosomal genomes and mirror mitochondrial DNA phylogenies, indicating replacement of both the mitochondrial and Y chromosomal gene pools in late Neanderthals. This replacement is plausible if the low effective population size of Neanderthals resulted in an increased genetic load in Neanderthals relative to modern humans.

RevDate: 2020-09-23

Bokelmann L, Glocke I, M Meyer (2020)

Reconstructing double-stranded DNA fragments on a single-molecule level reveals patterns of degradation in ancient samples.

Genome research pii:gr.263863.120 [Epub ahead of print].

Extensive manipulations involved in the preparation of DNA samples for sequencing have hitherto made it impossible to determine the precise structure of double-stranded DNA fragments being sequenced, such as the presence of blunt ends, single-stranded overhangs, or single-strand breaks. We here describe MatchSeq, a method that combines single-stranded DNA library preparation from diluted DNA samples with computational sequence matching, allowing the reconstruction of double-stranded DNA fragments on a single-molecule level. The application of MatchSeq to Neanderthal DNA, a particularly complex source of degraded DNA, reveals that 1- or 2-nt overhangs and blunt ends dominate the ends of ancient DNA molecules and that short gaps exist, which are predominantly caused by the loss of individual purines. We further show that deamination of cytosine to uracil occurs in both single- and double-stranded contexts close to the ends of molecules, and that single-stranded parts of DNA fragments are enriched in pyrimidines. MatchSeq provides unprecedented resolution for interrogating the structures of fragmented double-stranded DNA and can be applied to fragmented double-stranded DNA isolated from any biological source. The method relies on well-established laboratory techniques and can easily be integrated into routine data generation. This possibility is shown by the successful reconstruction of double-stranded DNA fragments from previously published single-stranded sequence data, allowing a more comprehensive characterization of the biochemical properties not only of ancient DNA but also of cell-free DNA from human blood plasma, a clinically relevant marker for the diagnosis and monitoring of disease.

RevDate: 2020-09-22

Orlando L (2020)

The Evolutionary and Historical Foundation of the Modern Horse: Lessons from Ancient Genomics.

Annual review of genetics [Epub ahead of print].

The domestication of the horse some 5,500 years ago followed those of dogs, sheep, goats, cattle, and pigs by ∼2,500-10,000 years. By providing fast transportation and transforming warfare, the horse had an impact on human history with no equivalent in the animal kingdom. Even though the equine sport industry has considerable economic value today, the evolutionary history underlying the emergence of the modern domestic horse remains contentious. In the last decade, novel sequencing technologies have revolutionized our capacity to sequence the complete genome of organisms, including from archaeological remains. Applied to horses, these technologies have provided unprecedented levels of information and have considerably changed models of horse domestication. This review illustrates how ancient DNA, especially ancient genomes, has inspired researchers to rethink the process by which horses were first domesticated and then diversified into a variety of breeds showing a range of traits that are useful to humans. Expected final online publication date for the Annual Review of Genetics, Volume 54 is November 23, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

RevDate: 2020-09-22

Ermakova GV, Kucheryavyy AV, Zaraisky AG, et al (2020)

Publisher Correction: Discovery of four Noggin genes in lampreys suggests two rounds of ancient genome duplication.

Communications biology, 3(1):532 pii:10.1038/s42003-020-01272-x.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

RevDate: 2020-09-21

Røed KH, Kvie KS, Losey RJ, et al (2020)

Temporal and structural genetic variation in reindeer (Rangifer tarandus) associated with the pastoral transition in Northwestern Siberia.

Ecology and evolution, 10(17):9060-9072 pii:ECE36314.

Just as the domestication of livestock is often cited as a key element in the Neolithic transition to settled, the emergence of large-scaled reindeer husbandry was a fundamental social transformation for the indigenous peoples of Arctic Eurasia. To better understand the history of reindeer domestication, and the genetic processes associated with the pastoral transition in the Eurasian Arctic, we analyzed archaeological and contemporary reindeer samples from Northwestern Siberia. The material represents Rangifer genealogies spanning from 15,000 years ago to the 18th century, as well as modern samples from the wild Taĭmyr population and from domestic herds managed by Nenetses. The wild and the domestic population are the largest populations of their kind in Northern Eurasia, and some Nenetses hold their domestic reindeer beside their wild cousins. Our analyses of 197 modern and 223 ancient mitochondrial DNA sequences revealed two genetic clusters, which are interpreted as representing the gene pools of contemporary domestic and past wild reindeer. Among a total of 137 different mitochondrial haplotypes identified in both the modern and archaeological samples, only 21 were detected in the modern domestic gene pool, while 11 of these were absent from the wild gene pool. The significant temporal genetic shift that we associate with the pastoral transition suggests that the emergence and spread of reindeer pastoralism in Northwestern Siberia originated with the translocation and subsequent selective breeding of a special type of animal from outside the region. The distinct and persistent domestic characteristics of the haplotype structure since the 18th century suggests little genetic exchange since then. The absence of the typical domestic clade in modern nearby wild populations suggests that the contemporary Nenets domestic breed feature an ancestry from outside its present main distribution, possibly from further South.

RevDate: 2020-09-21
CmpDate: 2020-09-21

Cassidy LM, Maoldúin RÓ, Kador T, et al (2020)

A dynastic elite in monumental Neolithic society.

Nature, 582(7812):384-388.

The nature and distribution of political power in Europe during the Neolithic era remains poorly understood1. During this period, many societies began to invest heavily in building monuments, which suggests an increase in social organization. The scale and sophistication of megalithic architecture along the Atlantic seaboard, culminating in the great passage tomb complexes, is particularly impressive2. Although co-operative ideology has often been emphasised as a driver of megalith construction1, the human expenditure required to erect the largest monuments has led some researchers to emphasize hierarchy3-of which the most extreme case is a small elite marshalling the labour of the masses. Here we present evidence that a social stratum of this type was established during the Neolithic period in Ireland. We sampled 44 whole genomes, among which we identify the adult son of a first-degree incestuous union from remains that were discovered within the most elaborate recess of the Newgrange passage tomb. Socially sanctioned matings of this nature are very rare, and are documented almost exclusively among politico-religious elites4-specifically within polygynous and patrilineal royal families that are headed by god-kings5,6. We identify relatives of this individual within two other major complexes of passage tombs 150 km to the west of Newgrange, as well as dietary differences and fine-scale haplotypic structure (which is unprecedented in resolution for a prehistoric population) between passage tomb samples and the larger dataset, which together imply hierarchy. This elite emerged against a backdrop of rapid maritime colonization that displaced a unique Mesolithic isolate population, although we also detected rare Irish hunter-gatherer introgression within the Neolithic population.

RevDate: 2020-09-18

Curry A (2020)

Ancient DNA tracks Vikings across Europe.

Science (New York, N.Y.), 369(6510):1416-1417.

RevDate: 2020-09-18

Martiniano R, Garrison E, Jones ER, et al (2020)

Removing reference bias and improving indel calling in ancient DNA data analysis by mapping to a sequence variation graph.

Genome biology, 21(1):250 pii:10.1186/s13059-020-02160-7.

BACKGROUND: During the last decade, the analysis of ancient DNA (aDNA) sequence has become a powerful tool for the study of past human populations. However, the degraded nature of aDNA means that aDNA molecules are short and frequently mutated by post-mortem chemical modifications. These features decrease read mapping accuracy and increase reference bias, in which reads containing non-reference alleles are less likely to be mapped than those containing reference alleles. Alternative approaches have been developed to replace the linear reference with a variation graph which includes known alternative variants at each genetic locus. Here, we evaluate the use of variation graph software vg to avoid reference bias for aDNA and compare with existing methods.

RESULTS: We use vg to align simulated and real aDNA samples to a variation graph containing 1000 Genome Project variants and compare with the same data aligned with bwa to the human linear reference genome. Using vg leads to a balanced allelic representation at polymorphic sites, effectively removing reference bias, and more sensitive variant detection in comparison with bwa, especially for insertions and deletions (indels). Alternative approaches that use relaxed bwa parameter settings or filter bwa alignments can also reduce bias but can have lower sensitivity than vg, particularly for indels.

CONCLUSIONS: Our findings demonstrate that aligning aDNA sequences to variation graphs effectively mitigates the impact of reference bias when analyzing aDNA, while retaining mapping sensitivity and allowing detection of variation, in particular indel variation, that was previously missed.

RevDate: 2020-09-17

Gibbon VE (2020)

African ancient DNA research requires robust ethics and permission protocols.

Nature reviews. Genetics pii:10.1038/s41576-020-00285-w [Epub ahead of print].

RevDate: 2020-09-17

Margaryan A, Lawson DJ, Sikora M, et al (2020)

Population genomics of the Viking world.

Nature, 585(7825):390-396.

The maritime expansion of Scandinavian populations during the Viking Age (about AD 750-1050) was a far-flung transformation in world history1,2. Here we sequenced the genomes of 442 humans from archaeological sites across Europe and Greenland (to a median depth of about 1×) to understand the global influence of this expansion. We find the Viking period involved gene flow into Scandinavia from the south and east. We observe genetic structure within Scandinavia, with diversity hotspots in the south and restricted gene flow within Scandinavia. We find evidence for a major influx of Danish ancestry into England; a Swedish influx into the Baltic; and Norwegian influx into Ireland, Iceland and Greenland. Additionally, we see substantial ancestry from elsewhere in Europe entering Scandinavia during the Viking Age. Our ancient DNA analysis also revealed that a Viking expedition included close family members. By comparing with modern populations, we find that pigmentation-associated loci have undergone strong population differentiation during the past millennium, and trace positively selected loci-including the lactase-persistence allele of LCT and alleles of ANKA that are associated with the immune response-in detail. We conclude that the Viking diaspora was characterized by substantial transregional engagement: distinct populations influenced the genomic makeup of different regions of Europe, and Scandinavia experienced increased contact with the rest of the continent.

RevDate: 2020-09-17

François O, F Jay (2020)

Factor analysis of ancient population genomic samples.

Nature communications, 11(1):4661 pii:10.1038/s41467-020-18335-6.

The recent years have seen a growing number of studies investigating evolutionary questions using ancient DNA. To address these questions, one of the most frequently-used method is principal component analysis (PCA). When PCA is applied to temporal samples, the sample dates are, however, ignored during analysis, leading to imperfect representations of samples in PC plots. Here, we present a factor analysis (FA) method in which individual scores are corrected for the effect of allele frequency drift over time. We obtained exact solutions for the estimates of corrected factors, and we provided a fast algorithm for their computation. Using computer simulations and ancient European samples, we compared geometric representations obtained from FA with PCA and with ancestry estimation programs. In admixture analyses, FA estimates agreed with tree-based statistics, and they were more accurate than those obtained from PCA projections and from ancestry estimation programs. A great advantage of FA over existing approaches is to improve descriptive analyses of ancient DNA samples without requiring inclusion of outgroup or present-day samples.

RevDate: 2020-09-17

Guimaraes S, Arbuckle BS, Peters J, et al (2020)

Ancient DNA shows domestic horses were introduced in the southern Caucasus and Anatolia during the Bronze Age.

Science advances, 6(38): pii:6/38/eabb0030.

Despite the important roles that horses have played in human history, particularly in the spread of languages and cultures, and correspondingly intensive research on this topic, the origin of domestic horses remains elusive. Several domestication centers have been hypothesized, but most of these have been invalidated through recent paleogenetic studies. Anatolia is a region with an extended history of horse exploitation that has been considered a candidate for the origins of domestic horses but has never been subject to detailed investigation. Our paleogenetic study of pre- and protohistoric horses in Anatolia and the Caucasus, based on a diachronic sample from the early Neolithic to the Iron Age (~8000 to ~1000 BCE) that encompasses the presumed transition from wild to domestic horses (4000 to 3000 BCE), shows the rapid and large-scale introduction of domestic horses at the end of the third millennium BCE. Thus, our results argue strongly against autochthonous independent domestication of horses in Anatolia.

RevDate: 2020-09-16

Rivollat M, Jeong C, Schiffels S, et al (2020)

Ancient genome-wide DNA from France highlights the complexity of interactions between Mesolithic hunter-gatherers and Neolithic farmers.

Science advances, 6(22): pii:6/22/eaaz5344.

Starting from 12,000 years ago in the Middle East, the Neolithic lifestyle spread across Europe via separate continental and Mediterranean routes. Genomes from early European farmers have shown a clear Near Eastern/Anatolian genetic affinity with limited contribution from hunter-gatherers. However, no genomic data are available from modern-day France, where both routes converged, as evidenced by a mosaic cultural pattern. Here, we present genome-wide data from 101 individuals from 12 sites covering today's France and Germany from the Mesolithic (N = 3) to the Neolithic (N = 98) (7000-3000 BCE). Using the genetic substructure observed in European hunter-gatherers, we characterize diverse patterns of admixture in different regions, consistent with both routes of expansion. Early western European farmers show a higher proportion of distinctly western hunter-gatherer ancestry compared to central/southeastern farmers. Our data highlight the complexity of the biological interactions during the Neolithic expansion by revealing major regional variations.

RevDate: 2020-09-16

Pawłowska J, Wollenburg JE, Zajączkowski M, et al (2020)

Planktonic foraminifera genomic variations reflect paleoceanographic changes in the Arctic: evidence from sedimentary ancient DNA.

Scientific reports, 10(1):15102 pii:10.1038/s41598-020-72146-9.

Deciphering the evolution of marine plankton is typically based on the study of microfossil groups. Cryptic speciation is common in these groups, and large intragenomic variations occur in ribosomal RNA genes of many morphospecies. In this study, we correlated the distribution of ribosomal amplicon sequence variants (ASVs) with paleoceanographic changes by analyzing the high-throughput sequence data assigned to Neogloboquadrina pachyderma in a 140,000-year-old sediment core from the Arctic Ocean. The sedimentary ancient DNA demonstrated the occurrence of various N. pachyderma ASVs whose occurrence and dominance varied through time. Most remarkable was the striking appearance of ASV18, which was nearly absent in older sediments but became dominant during the last glacial maximum and continues to persist today. Although the molecular ecology of planktonic foraminifera is still poorly known, the analysis of their intragenomic variations through time has the potential to provide new insight into the evolution of marine biodiversity and may lead to the development of new and important paleoceanographic proxies.

RevDate: 2020-09-16

Peyrégne S, BM Peter (2020)

AuthentiCT: a model of ancient DNA damage to estimate the proportion of present-day DNA contamination.

Genome biology, 21(1):246 pii:10.1186/s13059-020-02123-y.

Contamination from present-day DNA is a fundamental issue when studying ancient DNA from historical or archaeological material, and quantifying the amount of contamination is essential for downstream analyses. We present AuthentiCT, a command-line tool to estimate the proportion of present-day DNA contamination in ancient DNA datasets generated from single-stranded DNA libraries. The prediction is based solely on the patterns of post-mortem damage observed on ancient DNA sequences. The method has the power to quantify contamination from as few as 10,000 mapped sequences, making it particularly useful for analysing specimens that are poorly preserved or for which little data is available.

RevDate: 2020-09-14
CmpDate: 2020-09-14

Gansauge MT, Aximu-Petri A, Nagel S, et al (2020)

Manual and automated preparation of single-stranded DNA libraries for the sequencing of DNA from ancient biological remains and other sources of highly degraded DNA.

Nature protocols, 15(8):2279-2300.

It has been shown that highly fragmented DNA is most efficiently converted into DNA libraries for sequencing if both strands of the DNA fragments are processed independently. We present an updated protocol for library preparation from single-stranded DNA, which is based on the splinted ligation of an adapter oligonucleotide to the 3' ends of single DNA strands, the synthesis of a complementary strand using a DNA polymerase and the addition of a 5' adapter via blunt-end ligation. The efficiency of library preparation is determined individually for each sample using a spike-in oligonucleotide. The whole workflow, including library preparation, quantification and amplification, requires two work days for up to 16 libraries. Alternatively, we provide documentation and electronic protocols enabling automated library preparation of 96 samples in parallel on a Bravo NGS Workstation (Agilent Technologies). After library preparation, molecules with uninformative short inserts (shorter than ~30-35 base pairs) can be removed by polyacrylamide gel electrophoresis if desired.

RevDate: 2020-09-11

Nores R, Rena V, Angeletti SC, et al (2020)

Biological kinship in 750 year old human remains from Central Argentina with signs of interpersonal violence.

Forensic science, medicine, and pathology pii:10.1007/s12024-020-00296-3 [Epub ahead of print].

Human skeletal remains of an adult male (20-24 years old) and a juvenile (4-8 years old), dated to 750 ± 85 14C years BP, were found on the southern margin of Mar Chiquita Lagoon (Córdoba, Argentina). Both individuals show signs of being victims of interpersonal violence, with arrowheads associated with the remains and perimortem lesions on the juvenile, as well as an unusual form of burial, with the juvenile partially overlapped with the adult. The aim of this work is to study a possible kin relationship between these two individuals through ancient DNA analysis. Biological kinship was evaluated by autosomal and Y-chromosome STR (short tandem repeat) typing, PCR-APLP for SNP determination and hypervariable region I sequencing of the mitochondrial DNA. Genetic analyses indicated that these individuals shared the same Y-chromosomal haplotype but different mitochondrial lineages. The likelihood ratio based on autosomal loci indicates that the genetic profiles of the human remains would be more likely to be that indicating a father-son bond. The paleogenetic approach combined with forensic genetic methods applied to this study allowed us to confirm a hypothesis that originated in bioarchaeological evidence. This study constitutes a unique case in Argentina of kinship determination based on DNA profiles of human remains in an archaeological context of interpersonal violence. It is important to highlight the contribution made by these studies to address topics usually hidden in bioarchaeological studies, such as community organization, cultural customs and mortuary practices.

RevDate: 2020-09-11

Ermakova GV, Kucheryavyy AV, Zaraisky AG, et al (2020)

Discovery of four Noggin genes in lampreys suggests two rounds of ancient genome duplication.

Communications biology, 3(1):501 pii:10.1038/s42003-020-01234-3.

The secreted protein Noggin1 was the first discovered natural embryonic inducer produced by cells of the Spemann organizer. Thereafter, it was shown that vertebrates have a whole family of Noggin genes with different expression patterns and functional properties. For example, Noggin1 and Noggin2 inhibit the activity of BMP, Nodal/Activin and Wnt-beta-catenin signalling, while Noggin4 cannot suppress BMP but specifically modulates Wnt signalling. In this work, we described and investigated phylogeny and expression patterns of four Noggin genes in lampreys, which represent the most basally divergent group of extant vertebrates, the cyclostomes, belonging to the superclass Agnatha. Assuming that lampreys have Noggin homologues in all representatives of another superclass of vertebrates, the Gnathostomata, we propose a model for Noggin family evolution in vertebrates. This model is in agreement with the hypotheses suggesting two rounds of genome duplication in the ancestor of vertebrates before the divergence of Agnatha and Gnathostomata.

RevDate: 2020-09-09

Picin A, Hajdinjak M, Nowaczewska W, et al (2020)

New perspectives on Neanderthal dispersal and turnover from Stajnia Cave (Poland).

Scientific reports, 10(1):14778 pii:10.1038/s41598-020-71504-x.

The Micoquian is the broadest and longest enduring cultural facies of the Late Middle Palaeolithic that spread across the periglacial and boreal environments of Europe between Eastern France, Poland, and Northern Caucasus. Here, we present new data from the archaeological record of Stajnia Cave (Poland) and the paleogenetic analysis of a Neanderthal molar S5000, found in a Micoquian context. Our results demonstrate that the mtDNA genome of Stajnia S5000 dates to MIS 5a making the tooth the oldest Neanderthal specimen from Central-Eastern Europe. Furthermore, S5000 mtDNA has the fewest number of differences to mtDNA of Mezmaiskaya 1 Neanderthal from Northern Caucasus, and is more distant from almost contemporaneous Neanderthals of Scladina and Hohlenstein-Stadel. This observation and the technological affinity between Poland and the Northern Caucasus could be the result of increased mobility of Neanderthals that changed their subsistence strategy for coping with the new low biomass environments and the increased foraging radius of gregarious animals. The Prut and Dniester rivers were probably used as the main corridors of dispersal. The persistence of the Micoquian techno-complex in South-Eastern Europe infers that this axis of mobility was also used at the beginning of MIS 3 when a Neanderthal population turnover occurred in the Northern Caucasus.

RevDate: 2020-09-08

Ringbauer H, Steinrücken M, Fehren-Schmitz L, et al (2020)

Increased rate of close-kin unions in the central Andes in the half millennium before European contact.

Current biology : CB, 30(17):R980-R981.

Analyzing ancient DNA of the central Andes, Ringbauer and colleagues identify a markedly elevated rate of unions of closely related parents after ca. 1000 CE. This change of mating preferences sheds new light on a unique system of social organization based on ancestry ("ayllu") whereby within-group unions were preferred to facilitate sharing of resources.

RevDate: 2020-09-08

Duchene S, Lemey P, Stadler T, et al (2020)

Bayesian Evaluation of Temporal Signal in Measurably Evolving Populations.

Molecular biology and evolution pii:5867920 [Epub ahead of print].

Phylogenetic methods can use the sampling times of molecular sequence data to calibrate the molecular clock, enabling the estimation of evolutionary rates and timescales for rapidly evolving pathogens and data sets containing ancient DNA samples. A key aspect of such calibrations is whether a sufficient amount of molecular evolution has occurred over the sampling time window, that is, whether the data can be treated as having come from a measurably evolving population. Here, we investigate the performance of a fully Bayesian evaluation of temporal signal (BETS) in sequence data. The method involves comparing the fit to the data of two models: a model in which the data are accompanied by the actual (heterochronous) sampling times, and a model in which the samples are constrained to be contemporaneous (isochronous). We conducted simulations under a wide range of conditions to demonstrate that BETS accurately classifies data sets according to whether they contain temporal signal or not, even when there is substantial among-lineage rate variation. We explore the behavior of this classification in analyses of five empirical data sets: modern samples of A/H1N1 influenza virus, the bacterium Bordetella pertussis, coronaviruses from mammalian hosts, ancient DNA from Hepatitis B virus, and mitochondrial genomes of dog species. Our results indicate that BETS is an effective alternative to other tests of temporal signal. In particular, this method has the key advantage of allowing a coherent assessment of the entire model, including the molecular clock and tree prior which are essential aspects of Bayesian phylodynamic analyses.

RevDate: 2020-09-08
CmpDate: 2020-09-08

Ardelean CF, Becerra-Valdivia L, Pedersen MW, et al (2020)

Evidence of human occupation in Mexico around the Last Glacial Maximum.

Nature, 584(7819):87-92.

The initial colonization of the Americas remains a highly debated topic1, and the exact timing of the first arrivals is unknown. The earliest archaeological record of Mexico-which holds a key geographical position in the Americas-is poorly known and understudied. Historically, the region has remained on the periphery of research focused on the first American populations2. However, recent investigations provide reliable evidence of a human presence in the northwest region of Mexico3,4, the Chiapas Highlands5, Central Mexico6 and the Caribbean coast7-9 during the Late Pleistocene and Early Holocene epochs. Here we present results of recent excavations at Chiquihuite Cave-a high-altitude site in central-northern Mexico-that corroborate previous findings in the Americas10-17of cultural evidence that dates to the Last Glacial Maximum (26,500-19,000 years ago)18, and which push back dates for human dispersal to the region possibly as early as 33,000-31,000 years ago. The site yielded about 1,900 stone artefacts within a 3-m-deep stratified sequence, revealing a previously unknown lithic industry that underwent only minor changes over millennia. More than 50 radiocarbon and luminescence dates provide chronological control, and genetic, palaeoenvironmental and chemical data document the changing environments in which the occupants lived. Our results provide new evidence for the antiquity of humans in the Americas, illustrate the cultural diversity of the earliest dispersal groups (which predate those of the Clovis culture) and open new directions of research.

RevDate: 2020-09-07

Bakshi D, Nagpal A, Sharma V, et al (2020)

MassARRAY-based single nucleotide polymorphism analysis in breast cancer of north Indian population.

BMC cancer, 20(1):861 pii:10.1186/s12885-020-07361-8.

BACKGROUND: Breast Cancer (BC) is associated with inherited gene mutations. High throughput genotyping of BC samples has led to the identification and characterization of biomarkers for the diagnosis of BC. The most common genetic variants studied are SNPs (Single Nucleotide Polymorphisms) that determine susceptibility to an array of diseases thus serving as a potential tool for identifying the underlying causes of breast carcinogenesis.

METHODS: SNP genotyping employing the Agena MassARRAY offers a robust, sensitive, cost-effective method to assess multiple SNPs and samples simultaneously. In this present study, we analyzed 15 SNPs of 14 genes in 550 samples (150 cases and 400 controls). We identified four SNPs of genes TCF21, SLC19A1, DCC, and ERCC1 showing significant association with BC in the population under study.

RESULTS: The SNPs were rs12190287 (TCF21) having OR 1.713 (1.08-2.716 at 95% CI) p-value 0.022 (dominant), rs1051266 (SLC19A1) having OR 3.461 (2.136-5.609 at 95% CI) p-value 0.000000466 (dominant), rs2229080 (DCC) having OR 0.6867 (0.5123-0.9205 at 95% CI) p-value 0.0116 (allelic) and rs2298881 (ERCC1) having OR 0.669 (0.46-0.973 at 95% CI), p-value 0.035 (additive) respectively. The in-silico analysis was further used to fortify the above findings.

CONCLUSION: It is further anticipated that the variants should be evaluated in other population groups that may aid in understanding the genetic complexity and bridge the missing heritability.

RevDate: 2020-09-05

Eerkens JW, Ryder A, Evoy A, et al (2020)

Hydrogen isotopes in serial hair samples record season of death in a mummified child from 19th century San Francisco, CA.

American journal of physical anthropology [Epub ahead of print].

BACKGROUND: The mummified body of a small child was found in a sealed Barstow cast iron casket during construction activity in San Francisco in 2016. Using historical records and ancient DNA the child was determined to be Edith H. Cook. She was born 28 November, 1873 in the city of San Francisco, and died of "marasmus" on 13 October, 1876 also in San Francisco.

AIMS: Currently, there are few techniques for estimating human season of death in archaeological cases. Hydrogen isotope ratios (δ2H) in hair keratin is known to strongly correlate with drinking water. We explore δ2H in serial hair samples as a potential technique to estimate season of death by comparing the δ2H record from hair to the known date of death.

MATERIALS & METHODS: Approximately 50 hairs were removed from the scalp, aligned from the root, and cut into 5cm serial sections, each representing approximately 2 weeks of growth, and the total sequence a total of 1 year of growth. δ2H was measured on each 5cm segment and compared to previously-reported δ13C, δ15N, and δ34S values.

RESULTS: δ2H in the serial hair samples ranged between -56‰ and -48‰, consistent with her water values recorded in surface waters from San Francisco, and follow a sinusoidal pattern. Decreasing δ2H in terminal samples before death suggest Fall as the season of death, consistent with the known date of death.

DISCUSSION: This test case shows that archaeological hair preserves a seasonal signature in the form of changing keratin δ2H values that correlate to changing δ2H in surface drinking water. Terminal values in root record water ingested during the final week(s) before death.

CONCLUSIONS: We argue that this technique can be used to estimate season of death in future archaeological or forensic cases where hair has been preserved but date of death is unknown.

RevDate: 2020-09-03
CmpDate: 2020-09-03

Spinney L (2020)

Smallpox and other viruses plagued humans much earlier than suspected.

Nature, 584(7819):30-32.

RevDate: 2020-09-03

Lord E, Collins C, deFrance S, et al (2020)

Author Correction: Ancient DNA of Guinea Pigs (Cavia spp.) Indicates a Probable New Center of Domestication and Pathways of Global Distribution.

Scientific reports, 10(1):14783 pii:10.1038/s41598-020-71841-x.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

RevDate: 2020-09-02

Karpinski E, Hackenberger D, Zazula G, et al (2020)

American mastodon mitochondrial genomes suggest multiple dispersal events in response to Pleistocene climate oscillations.

Nature communications, 11(1):4048 pii:10.1038/s41467-020-17893-z.

Pleistocene glacial-interglacial cycles are correlated with dramatic temperature oscillations. Examining how species responded to these natural fluctuations can provide valuable insights into the impacts of present-day anthropogenic climate change. Here we present a phylogeographic study of the extinct American mastodon (Mammut americanum), based on 35 complete mitochondrial genomes. These data reveal the presence of multiple lineages within this species, including two distinct clades from eastern Beringia. Our molecular date estimates suggest that these clades arose at different times, supporting a pattern of repeated northern expansion and local extirpation in response to glacial cycling. Consistent with this hypothesis, we also note lower levels of genetic diversity among northern mastodons than in endemic clades south of the continental ice sheets. The results of our study highlight the complex relationships between population dispersals and climate change, and can provide testable hypotheses for extant species expected to experience substantial biogeographic impacts from rising temperatures.

RevDate: 2020-08-29

Neukamm J, Pfrengle S, Molak M, et al (2020)

2000-year-old pathogen genomes reconstructed from metagenomic analysis of Egyptian mummified individuals.

BMC biology, 18(1):108 pii:10.1186/s12915-020-00839-8.

BACKGROUND: Recent advances in sequencing have facilitated large-scale analyses of the metagenomic composition of different samples, including the environmental microbiome of air, water, and soil, as well as the microbiome of living humans and other animals. Analyses of the microbiome of ancient human samples may provide insights into human health and disease, as well as pathogen evolution, but the field is still in its very early stages and considered highly challenging.

RESULTS: The metagenomic and pathogen content of Egyptian mummified individuals from different time periods was investigated via genetic analysis of the microbial composition of various tissues. The analysis of the dental calculus' microbiome identified Red Complex bacteria, which are correlated with periodontal diseases. From bone and soft tissue, genomes of two ancient pathogens, a 2200-year-old Mycobacterium leprae strain and a 2000-year-old human hepatitis B virus, were successfully reconstructed.

CONCLUSIONS: The results show the reliability of metagenomic studies on Egyptian mummified individuals and the potential to use them as a source for the extraction of ancient pathogen DNA.

RevDate: 2020-08-24
CmpDate: 2020-08-24

Brunel S, Bennett EA, Cardin L, et al (2020)

Ancient genomes from present-day France unveil 7,000 years of its demographic history.

Proceedings of the National Academy of Sciences of the United States of America, 117(23):12791-12798.

Genomic studies conducted on ancient individuals across Europe have revealed how migrations have contributed to its present genetic landscape, but the territory of present-day France has yet to be connected to the broader European picture. We generated a large dataset comprising the complete mitochondrial genomes, Y-chromosome markers, and genotypes of a number of nuclear loci of interest of 243 individuals sampled across present-day France over a period spanning 7,000 y, complemented with a partially overlapping dataset of 58 low-coverage genomes. This panel provides a high-resolution transect of the dynamics of maternal and paternal lineages in France as well as of autosomal genotypes. Parental lineages and genomic data both revealed demographic patterns in France for the Neolithic and Bronze Age transitions consistent with neighboring regions, first with a migration wave of Anatolian farmers followed by varying degrees of admixture with autochthonous hunter-gatherers, and then substantial gene flow from individuals deriving part of their ancestry from the Pontic steppe at the onset of the Bronze Age. Our data have also highlighted the persistence of Magdalenian-associated ancestry in hunter-gatherer populations outside of Spain and thus provide arguments for an expansion of these populations at the end of the Paleolithic Period more northerly than what has been described so far. Finally, no major demographic changes were detected during the transition between the Bronze and Iron Ages.

RevDate: 2020-08-23

Hofreiter M, S Hartmann (2020)

Reconstructing protein-coding sequences from ancient DNA.

Methods in enzymology, 642:21-33.

Obtaining information about functional details of proteins of extinct species is of critical importance for a better understanding of the real-life appearance, behavior and ecology of these lost entries in the book of life. In this chapter, we discuss the possibilities to retrieve the necessary DNA sequence information from paleogenomic data obtained from fossil specimens, which can then be used to express and subsequently analyze the protein of interest. We discuss the problems specific to ancient DNA, including miscoding lesions, short read length and incomplete paleogenome assemblies. Finally, we discuss an alternative, but currently rarely used approach, direct PCR amplification, which is especially useful for comparatively short proteins.

RevDate: 2020-08-22

He Z, Dai X, Beaumont M, et al (2020)

Detecting and Quantifying Natural Selection at Two Linked Loci from Time Series Data of Allele Frequencies with Forward-in-Time Simulations.

Genetics pii:genetics.120.303463 [Epub ahead of print].

Recent advances in DNA sequencing techniques have made it possible to monitor genomes in great detail over time. This improvement provides an opportunity for us to study natural selection based on time serial samples of genomes while accounting for genetic recombination effect and local linkage information. Such time series genomic data allow for more accurate estimation of population genetic parameters and hypothesis testing on the recent action of natural selection. In this work, we develop a novel Bayesian statistical framework for inferring natural selection at a pair of linked loci by capitalising on the temporal aspect of DNA data with the additional flexibility of modelling the sampled chromosomes that contain unknown alleles. Our approach is built on a hidden Markov model where the underlying process is a two-locus Wright-Fisher diffusion with selection, which enables us to explicitly model genetic recombination and local linkage. The posterior probability distribution for selection coefficients is computed by applying the particle marginal Metropolis-Hastings algorithm, which allows us to efficiently calculate the likelihood. We evaluate the performance of our Bayesian inference procedure through extensive simulations, showing that our approach can deliver accurate estimates of selection coefficients, and the addition of genetic recombination and local linkage brings about significant improvement in the inference of natural selection. We also illustrate the utility of our method on real data with an application to ancient DNA data associated with white spotting patterns in horses.

RevDate: 2020-08-20

Pratas D, Toppinen M, Pyöriä L, et al (2020)

A hybrid pipeline for reconstruction and analysis of viral genomes at multi-organ level.

GigaScience, 9(8):.

BACKGROUND: Advances in sequencing technologies have enabled the characterization of multiple microbial and host genomes, opening new frontiers of knowledge while kindling novel applications and research perspectives. Among these is the investigation of the viral communities residing in the human body and their impact on health and disease. To this end, the study of samples from multiple tissues is critical, yet, the complexity of such analysis calls for a dedicated pipeline. We provide an automatic and efficient pipeline for identification, assembly, and analysis of viral genomes that combines the DNA sequence data from multiple organs. TRACESPipe relies on cooperation among 3 modalities: compression-based prediction, sequence alignment, and de novo assembly. The pipeline is ultra-fast and provides, additionally, secure transmission and storage of sensitive data.

FINDINGS: TRACESPipe performed outstandingly when tested on synthetic and ex vivo datasets, identifying and reconstructing all the viral genomes, including those with high levels of single-nucleotide polymorphisms. It also detected minimal levels of genomic variation between different organs.

CONCLUSIONS: TRACESPipe's unique ability to simultaneously process and analyze samples from different sources enables the evaluation of within-host variability. This opens up the possibility to investigate viral tissue tropism, evolution, fitness, and disease associations. Moreover, additional features such as DNA damage estimation and mitochondrial DNA reconstruction and analysis, as well as exogenous-source controls, expand the utility of this pipeline to other fields such as forensics and ancient DNA studies. TRACESPipe is released under GPLv3 and is available for free download at https://github.com/viromelab/tracespipe.

RevDate: 2020-08-19

Woods R, Turvey ST, Brace S, et al (2020)

Rapid size change associated with intra-island evolutionary radiation in extinct Caribbean "island-shrews".

BMC evolutionary biology, 20(1):106 pii:10.1186/s12862-020-01668-7.

BACKGROUND: The Caribbean offers a unique opportunity to study evolutionary dynamics in insular mammals. However, the recent extinction of most Caribbean non-volant mammals has obstructed evolutionary studies, and poor DNA preservation associated with tropical environments means that very few ancient DNA sequences are available for extinct vertebrates known from the region's Holocene subfossil record. The endemic Caribbean eulipotyphlan family Nesophontidae ("island-shrews") became extinct ~ 500 years ago, and the taxonomic validity of many Nesophontes species and their wider evolutionary dynamics remain unclear. Here we use both morphometric and palaeogenomic methods to clarify the status and evolutionary history of Nesophontes species from Hispaniola, the second-largest Caribbean island.

RESULTS: Principal component analysis of 65 Nesophontes mandibles from late Quaternary fossil sites across Hispaniola identified three non-overlapping morphometric clusters, providing statistical support for the existence of three size-differentiated Hispaniolan Nesophontes species. We were also able to extract and sequence ancient DNA from a ~ 750-year-old specimen of Nesophontes zamicrus, the smallest non-volant Caribbean mammal, including a whole-mitochondrial genome and partial nuclear genes. Nesophontes paramicrus (39-47 g) and N. zamicrus (~ 10 g) diverged recently during the Middle Pleistocene (mean estimated divergence = 0.699 Ma), comparable to the youngest species splits in Eulipotyphla and other mammal groups. Pairwise genetic distance values for N. paramicrus and N. zamicrus based on mitochondrial and nuclear genes are low, but fall within the range of comparative pairwise data for extant eulipotyphlan species-pairs.

CONCLUSIONS: Our combined morphometric and palaeogenomic analyses provide evidence for multiple co-occurring species and rapid body size evolution in Hispaniolan Nesophontes, in contrast to patterns of genetic and morphometric differentiation seen in Hispaniola's extant non-volant land mammals. Different components of Hispaniola's mammal fauna have therefore exhibited drastically different rates of morphological evolution. Morphological evolution in Nesophontes is also rapid compared to patterns across the Eulipotyphla, and our study provides an important new example of rapid body size change in a small-bodied insular vertebrate lineage. The Caribbean was a hotspot for evolutionary diversification as well as preserving ancient biodiversity, and studying the surviving representatives of its mammal fauna is insufficient to reveal the evolutionary patterns and processes that generated regional diversity.

RevDate: 2020-08-17
CmpDate: 2020-08-17

Ning C, Li T, Wang K, et al (2020)

Ancient genomes from northern China suggest links between subsistence changes and human migration.

Nature communications, 11(1):2700 pii:10.1038/s41467-020-16557-2.

Northern China harbored the world's earliest complex societies based on millet farming, in two major centers in the Yellow (YR) and West Liao (WLR) River basins. Until now, their genetic histories have remained largely unknown. Here we present 55 ancient genomes dating to 7500-1700 BP from the YR, WLR, and Amur River (AR) regions. Contrary to the genetic stability in the AR, the YR and WLR genetic profiles substantially changed over time. The YR populations show a monotonic increase over time in their genetic affinity with present-day southern Chinese and Southeast Asians. In the WLR, intensification of farming in the Late Neolithic is correlated with increased YR affinity while the inclusion of a pastoral economy in the Bronze Age was correlated with increased AR affinity. Our results suggest a link between changes in subsistence strategy and human migration, and fuel the debate about archaeolinguistic signatures of past human migration.

RevDate: 2020-08-15

Majander K, Pfrengle S, Kocher A, et al (2020)

Ancient Bacterial Genomes Reveal a High Diversity of Treponema pallidum Strains in Early Modern Europe.

Current biology : CB pii:S0960-9822(20)31083-6 [Epub ahead of print].

Syphilis is a globally re-emerging disease, which has marked European history with a devastating epidemic at the end of the 15th century. Together with non-venereal treponemal diseases, like bejel and yaws, which are found today in subtropical and tropical regions, it currently poses a substantial health threat worldwide. The origins and spread of treponemal diseases remain unresolved, including syphilis' potential introduction into Europe from the Americas. Here, we present the first genetic data from archaeological human remains reflecting a high diversity of Treponema pallidum in early modern Europe. Our study demonstrates that a variety of strains related to both venereal syphilis and yaws-causing T. pallidum subspecies were already present in Northern Europe in the early modern period. We also discovered a previously unknown T. pallidum lineage recovered as a sister group to yaws- and bejel-causing lineages. These findings imply a more complex pattern of geographical distribution and etiology of early treponemal epidemics than previously understood.

RevDate: 2020-08-15

Lord E, Dussex N, Kierczak M, et al (2020)

Pre-extinction Demographic Stability and Genomic Signatures of Adaptation in the Woolly Rhinoceros.

Current biology : CB pii:S0960-9822(20)31071-X [Epub ahead of print].

Ancient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna. However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction. The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP). While humans and climate change have been proposed as potential causes of extinction [1-3], knowledge is limited on how the woolly rhinoceros was impacted by human arrival and climatic fluctuations [2]. Here, we use one complete nuclear genome and 14 mitogenomes to investigate the demographic history of woolly rhinoceros leading up to its extinction. Unlike other northern megafauna, the effective population size of woolly rhinoceros likely increased at 29.7 ka BP and subsequently remained stable until close to the species' extinction. Analysis of the nuclear genome from a ∼18.5-ka-old specimen did not indicate any increased inbreeding or reduced genetic diversity, suggesting that the population size remained steady for more than 13 ka following the arrival of humans [4]. The population contraction leading to extinction of the woolly rhinoceros may have thus been sudden and mostly driven by rapid warming in the Bølling-Allerød interstadial. Furthermore, we identify woolly rhinoceros-specific adaptations to arctic climate, similar to those of the woolly mammoth. This study highlights how species respond differently to climatic fluctuations and further illustrates the potential of palaeogenomics to study the evolutionary history of extinct species.

RevDate: 2020-08-13

Ford BM, Cornellas A, Leonard JA, et al (2020)

Spatiotemporal analyses suggest the role of glacial history and the ice-free corridor in shaping American badger population genetic variation.

Ecology and evolution, 10(15):8345-8357 pii:ECE36541.

Recurring glacial cycles through the Quaternary period drastically altered the size and distribution of natural populations of North American flora and fauna. The "southerly refugia model" has been the longstanding framework for testing the effects of glaciation on contemporary genetic patterns; however, insights from ancient DNA have contributed to the reconstruction of more complex histories for some species. The American badger, Taxidea taxus, provides an interesting species for exploring the genetic legacy of glacial history, having been hypothesized to have postglacially emerged from a single, southerly refugium to recolonize northern latitudes. However, previous studies have lacked genetic sampling from areas where distinct glacial refugia have been hypothesized, including the Pacific Northwest and American Far North (Yukon, Alaska). In order to further investigate the phylogeographic history of American badgers, we collected mitochondrial DNA sequence data from ancient subfossil material collected within the historical range (Alaska, Yukon) and combined them with new and previously published data from across the species' contemporary distribution (n = 1,207). We reconstructed a mostly unresolved phylogenetic tree and star-like haplotype network indicative of emergence from a largely panmictic glacial refugium and recent population expansion, the latter further punctuated by significantly negative Tajima's D and Fu's Fs values. Although directionality of migration cannot be unequivocally inferred, the moderate to high levels of genetic variation exhibited by American badgers, alongside the low frequency of haplotypes with indels in the Midwest, suggest a potential recolonization into central North America after the hypothesized ice-free corridor reopened ~13,000 years ago. Overall, the expanded reconstruction of phylogeographic history of American badgers offers a broader understanding of contemporary range-wide patterns and identifies unique genetic units that can likely be used to inform conservation of at-risk populations at the northern periphery.

RevDate: 2020-08-11

Nakatsuka N, Harney É, Mallick S, et al (2020)

ContamLD: estimation of ancient nuclear DNA contamination using breakdown of linkage disequilibrium.

Genome biology, 21(1):199 pii:10.1186/s13059-020-02111-2.

We report a method called ContamLD for estimating autosomal ancient DNA (aDNA) contamination by measuring the breakdown of linkage disequilibrium in a sequenced individual due to the introduction of contaminant DNA. ContamLD leverages the idea that contaminants should have haplotypes uncorrelated to those of the studied individual. Using simulated data, we confirm that ContamLD accurately infers contamination rates with low standard errors: for example, less than 1.5% standard error in cases with less than 10% contamination and 500,000 sequences covering SNPs. This method is optimized for application to aDNA, taking advantage of characteristic aDNA damage patterns to provide calibrated contamination estimates, and is available at https://github.com/nathan-nakatsuka/ContamLD .

RevDate: 2020-08-11

Sabin S, Herbig A, Vågene ÅJ, et al (2020)

A seventeenth-century Mycobacterium tuberculosis genome supports a Neolithic emergence of the Mycobacterium tuberculosis complex.

Genome biology, 21(1):201 pii:10.1186/s13059-020-02112-1.

BACKGROUND: Although tuberculosis accounts for the highest mortality from a bacterial infection on a global scale, questions persist regarding its origin. One hypothesis based on modern Mycobacterium tuberculosis complex (MTBC) genomes suggests their most recent common ancestor followed human migrations out of Africa approximately 70,000 years before present. However, studies using ancient genomes as calibration points have yielded much younger dates of less than 6000 years. Here, we aim to address this discrepancy through the analysis of the highest-coverage and highest-quality ancient MTBC genome available to date, reconstructed from a calcified lung nodule of Bishop Peder Winstrup of Lund (b. 1605-d. 1679).

RESULTS: A metagenomic approach for taxonomic classification of whole DNA content permitted the identification of abundant DNA belonging to the human host and the MTBC, with few non-TB bacterial taxa comprising the background. Genomic enrichment enabled the reconstruction of a 141-fold coverage M. tuberculosis genome. In utilizing this high-quality, high-coverage seventeenth-century genome as a calibration point for dating the MTBC, we employed multiple Bayesian tree models, including birth-death models, which allowed us to model pathogen population dynamics and data sampling strategies more realistically than those based on the coalescent.

CONCLUSIONS: The results of our metagenomic analysis demonstrate the unique preservation environment calcified nodules provide for DNA. Importantly, we estimate a most recent common ancestor date for the MTBC of between 2190 and 4501 before present and for Lineage 4 of between 929 and 2084 before present using multiple models, confirming a Neolithic emergence for the MTBC.

RevDate: 2020-08-09

He Z, Dai X, Beaumont M, et al (2020)

Estimation of Natural Selection and Allele Age from Time Series Allele Frequency Data Using a Novel Likelihood-Based Approach.

Genetics pii:genetics.120.303400 [Epub ahead of print].

Temporally spaced genetic data allow for more accurate inference of population genetic parameters and hypothesis testing on the recent action of natural selection. In this work, we develop a novel likelihood-based method for jointly estimating selection coefficient and allele age from time series data of allele frequencies. Our approach is based on a hidden Markov model where the underlying process is a Wright-Fisher diffusion conditioned to survive until the time of the most recent sample. This formulation circumvents the assumption required in existing methods that the allele is created by mutation at a certain low frequency. We calculate the likelihood by numerically solving the resulting Kolmogorov backward equation backwards in time while re-weighting the solution with the emission probabilities of the observation at each sampling time point. This procedure reduces the two-dimensional numerical search for the maximum of the likelihood surface for both the selection coefficient and the allele age to a one-dimensional search over the selection coefficient only. We illustrate through extensive simulations that our method can produce accurate estimates of the selection coefficient and the allele age under both constant and non-constant demographic histories. We apply our approach to re-analyse ancient DNA data associated with horse base coat colours. We find that ignoring demographic histories or grouping raw samples can significantly bias the inference results.

RevDate: 2020-08-08

Parolin ML, Cortés LI, Basso N, et al (2020)

New Evidence of Ancient Mitochondrial DNA of the Southern Andes (Calchaquí Valleys, Northwest Argentina, 3,600-1,900 Years before Present).

Human biology, 91(4):225-247.

Genetic studies on pre-Hispanic populations of the Southern Andes have been increasing steadily in the last decade. Nevertheless, ancient DNA characterization of Formative Period archaeological human remains is particularly scant, especially for Northwest Argentina. To expand current information on genetic characterization of the first agricultural communities of the southern Calchaquí Valleys, we present and discuss the first mitochondrial ancient DNA information obtained on samples dated to ca. 3,600-1,900 years before present from the Cajón Valley, Catamarca Province. Reproducible mtDNA hypervariable region 1 (HVR-1) sequences were obtained in seven individuals. Mitochondrial HVR-1 haplotypes were assigned to three of the four founding haplogroups, D1 (57.1%), C1 (28.5%), and B2 (14.2%), with absence of A2. Our results show that the Cajón Valley sample, with predominance of D1 and C1, differs from that commonly observed in ancient and modern Andean populations, which usually show a high prevalence of haplogroup B2. The fact that the Cajón Valley and Pampa Grande (Salta Province, Argentina) share a prevalence of haplogroup D1 could provide additional evidence to support possible genetic affinities between the valleys and the eastern sub-Andean region during the Formative Period in Northwest Argentina, expanding the archaeological evidence of contact between both populations. Future complete mitogenomic analysis will provide substantial information to formulate new hypotheses about the origins and phylogenetic relationships between the individuals of the Cajón Valley and other groups from the Andes, Gran Chaco, and the Amazon.

RevDate: 2020-08-08

Wagner JK, Colwell C, Claw KG, et al (2020)

Fostering Responsible Research on Ancient DNA.

American journal of human genetics, 107(2):183-195.

Anticipating and addressing the social implications of scientific work is a fundamental responsibility of all scientists. However, expectations for ethically sound practices can evolve over time as the implications of science come to be better understood. Contemporary researchers who work with ancient human remains, including those who conduct ancient DNA research, face precisely this challenge as it becomes clear that practices such as community engagement are needed to address the important social implications of this work. To foster and promote ethical engagement between researchers and communities, we offer five practical recommendations for ancient DNA researchers: (1) formally consult with communities; (2) address cultural and ethical considerations; (3) engage communities and support capacity building; (4) develop plans to report results and manage data; and (5) develop plans for long-term responsibility and stewardship. Ultimately, every member of a research team has an important role in fostering ethical research on ancient DNA.

RevDate: 2020-08-07

Barrera-Redondo J, Piñero D, LE Eguiarte (2020)

Genomic, Transcriptomic and Epigenomic Tools to Study the Domestication of Plants and Animals: A Field Guide for Beginners.

Frontiers in genetics, 11:742.

In the last decade, genomics and the related fields of transcriptomics and epigenomics have revolutionized the study of the domestication process in plants and animals, leading to new discoveries and new unresolved questions. Given that some domesticated taxa have been more studied than others, the extent of genomic data can range from vast to nonexistent, depending on the domesticated taxon of interest. This review is meant as a rough guide for students and academics that want to start a domestication research project using modern genomic tools, as well as for researchers already conducting domestication studies that are interested in following a genomic approach and looking for alternate strategies (cheaper or more efficient) and future directions. We summarize the theoretical and technical background needed to carry out domestication genomics, starting from the acquisition of a reference genome and genome assembly, to the sampling design for population genomics, paleogenomics, transcriptomics, epigenomics and experimental validation of domestication-related genes. We also describe some examples of the aforementioned approaches and the relevant discoveries they made to understand the domestication of the studied taxa.

RevDate: 2020-08-04

Nakatsuka N, Luisi P, Motti JMB, et al (2020)

Ancient genomes in South Patagonia reveal population movements associated with technological shifts and geography.

Nature communications, 11(1):3868 pii:10.1038/s41467-020-17656-w.

Archaeological research documents major technological shifts among people who have lived in the southern tip of South America (South Patagonia) during the last thirteen millennia, including the development of marine-based economies and changes in tools and raw materials. It has been proposed that movements of people spreading culture and technology propelled some of these shifts, but these hypotheses have not been tested with ancient DNA. Here we report genome-wide data from 20 ancient individuals, and co-analyze it with previously reported data. We reveal that immigration does not explain the appearance of marine adaptations in South Patagonia. We describe partial genetic continuity since ~6600 BP and two later gene flows correlated with technological changes: one between 4700-2000 BP that affected primarily marine-based groups, and a later one impacting all <2000 BP groups. From ~2200-1200 BP, mixture among neighbors resulted in a cline correlated to geographic ordering along the coast.

RevDate: 2020-06-29
CmpDate: 2020-06-29

Hublin JJ, Sirakov N, Aldeias V, et al (2020)

Initial Upper Palaeolithic Homo sapiens from Bacho Kiro Cave, Bulgaria.

Nature, 581(7808):299-302.

The Middle to Upper Palaeolithic transition in Europe witnessed the replacement and partial absorption of local Neanderthal populations by Homo sapiens populations of African origin1. However, this process probably varied across regions and its details remain largely unknown. In particular, the duration of chronological overlap between the two groups is much debated, as are the implications of this overlap for the nature of the biological and cultural interactions between Neanderthals and H. sapiens. Here we report the discovery and direct dating of human remains found in association with Initial Upper Palaeolithic artefacts2, from excavations at Bacho Kiro Cave (Bulgaria). Morphological analysis of a tooth and mitochondrial DNA from several hominin bone fragments, identified through proteomic screening, assign these finds to H. sapiens and link the expansion of Initial Upper Palaeolithic technologies with the spread of H. sapiens into the mid-latitudes of Eurasia before 45 thousand years ago3. The excavations yielded a wealth of bone artefacts, including pendants manufactured from cave bear teeth that are reminiscent of those later produced by the last Neanderthals of western Europe4-6. These finds are consistent with models based on the arrival of multiple waves of H. sapiens into Europe coming into contact with declining Neanderthal populations7,8.

RevDate: 2020-08-03

Mathieson I (2020)

Human adaptation over the past 40,000 years.

Current opinion in genetics & development, 62:97-104 pii:S0959-437X(20)30101-5 [Epub ahead of print].

Over the past few years several methodological and data-driven advances have greatly improved our ability to robustly detect genomic signatures of selection in humans. New methods applied to large samples of present-day genomes provide increased power, while ancient DNA allows precise estimation of timing and tempo. However, despite these advances, we are still limited in our ability to translate these signatures into understanding about which traits were actually under selection, and why. Combining information from different populations and timescales may allow interpretation of selective sweeps. Other modes of selection have proved more difficult to detect. In particular, despite strong evidence of the polygenicity of most human traits, evidence for polygenic selection is weak, and its importance in recent human evolution remains unclear. Balancing selection and archaic introgression seem important for the maintenance of potentially adaptive immune diversity, but perhaps less so for other traits.

RevDate: 2020-08-03

Shillito LM, Whelton HL, Blong JC, et al (2020)

Pre-Clovis occupation of the Americas identified by human fecal biomarkers in coprolites from Paisley Caves, Oregon.

Science advances, 6(29):eaba6404 pii:aba6404.

When and how people first settled in the Americas is an ongoing area of research and debate. The earliest sites typically only contain lithic artifacts that cannot be directly dated. The lack of human skeletal remains in these early contexts means that alternative sources of evidence are needed. Coprolites, and the DNA contained within them, are one such source, but unresolved issues concerning ancient DNA taphonomy and potential for contamination make this approach problematic. Here, we use fecal lipid biomarkers to demonstrate unequivocally that three coprolites dated to pre-Clovis are human, raise questions over the reliance on DNA methods, and present a new radiocarbon date on basketry further supporting pre-Clovis human occupation.

RevDate: 2020-07-29

Del Corvo M, Bongiorni S, Stefanon B, et al (2020)

Genome-Wide DNA Methylation and Gene Expression Profiles in Cows Subjected to Different Stress Level as Assessed by Cortisol in Milk.

Genes, 11(8): pii:genes11080850.

Dairy cattle health, wellbeing and productivity are deeply affected by stress. Its influence on metabolism and immune response is well known, but the underlying epigenetic mechanisms require further investigation. In this study, we compared DNA methylation and gene expression signatures between two dairy cattle populations falling in the high- and low-variant tails of the distribution of milk cortisol concentration (MC), a neuroendocrine marker of stress in dairy cows. Reduced Representation Bisulfite Sequencing was used to obtain a methylation map from blood samples of these animals. The high and low groups exhibited similar amounts of methylated CpGs, while we found differences among non-CpG sites. Significant methylation changes were detected in 248 genes. We also identified significant fold differences in the expression of 324 genes. KEGG and Gene Ontology (GO) analysis showed that genes of both groups act together in several pathways, such as nervous system activity, immune regulatory functions and glucocorticoid metabolism. These preliminary results suggest that, in livestock, cortisol secretion could act as a trigger for epigenetic regulation and that peripheral changes in methylation can provide an insight into central nervous system functions.

RevDate: 2020-07-21

Cao X, Xu X, Bian R, et al (2020)

Sedimentary ancient DNA metabarcoding delineates the contrastingly temporal change of lake cyanobacterial communities.

Water research, 183:116077 pii:S0043-1354(20)30614-X [Epub ahead of print].

Harmful cyanobacterial blooms consisting of toxic taxa can produce a wide variety of toxins to threaten water quality, ecosystem functions and services. Of greater concern was the changing patterns of cyanobacterial assemblage were not well understood due to the lack of long-term monitoring data over the temporal scale. Biodiversity change in cyanobacterial community and paleoenvironmental variables over the past 170 years in Lake Chenghai were investigated based on sedimentary ancient DNA metabarcoding and traditional paleolimnological analysis. The results showed species richness and homogenization of cyanobacterial assemblage increased in the most recent decades, which were synchronized with the growth of artificial fertilization and decline in precipitation. Cyanobacterial co-occurrence network analysis revealed more complex interactions and weak community stability after the change point of ∼1987, while the rare cyanobacterial genera such as Anabaena, Planktothrix, Oscillatoria and Microcystis were identified to be keystone taxa affecting cyanobacterial assemblage. Furthermore, an increase of toxin-producing cyanobacterial taxa was significantly and positively associated with TN and TP, as well as TN/IP and TN/TP, which was verified by quantitative real-time PCR of mcyA and rpoC1 genes. Threshold in total nitrogen (TN) concentration should be targeted no more than 0.60 mg/L to alleviate nuisance cyanobacterial blooms in Lake Chenghai. These findings reinforce the comprehensive understanding for the long-term dynamics of cyanobacterial assemblage responding to environmental change, which could contribute to proactively regulate environmental conditions for avoiding undesirable ecological consequences.

LOAD NEXT 100 CITATIONS

ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

ESP Content

When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

ESP Help

Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @ gmail.com

Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).

Timelines

ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.

Biographies

Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 07 JUL 2018 )