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Bibliography on: Paleontology Meets Genomics — Sequencing Ancient DNA

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ESP: PubMed Auto Bibliography 25 Oct 2020 at 01:49 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®)

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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.

RevDate: 2020-07-20

Zhang M, Q Fu (2020)

Human evolutionary history in Eastern Eurasia using insights from ancient DNA.

Current opinion in genetics & development, 62:78-84 pii:S0959-437X(20)30109-X [Epub ahead of print].

Advances in ancient genomics are providing unprecedented insight into modern human history. Here, we review recent progress uncovering prehistoric populations in Eastern Eurasia based on ancient DNA studies from the Upper Pleistocene to the Holocene. Many ancient populations existed during the Upper Pleistocene of Eastern Eurasia-some with no substantial ancestry related to present-day populations, some with an affinity to East Asians, and some who contributed to Native Americans. By the Holocene, the genetic composition across East Asia greatly shifted, with several substantial migrations. Three are southward: an increase in northern East Asian-related ancestry in southern East Asia; movement of East Asian-related ancestry into Southeast Asia, mixing with Basal Asian ancestry; and movement of southern East Asian ancestry to islands of Southeast Asia and the Southwest Pacific through the expansion of Austronesians. We anticipate that additional ancient DNA will magnify our understanding of the genetic history in Eastern Eurasia.

RevDate: 2020-07-20

Duggan AT, Klunk J, Porter AF, et al (2020)

The origins and genomic diversity of American Civil War Era smallpox vaccine strains.

Genome biology, 21(1):175 pii:10.1186/s13059-020-02079-z.

Vaccination has transformed public health, most notably including the eradication of smallpox. Despite its profound historical importance, little is known of the origins and diversity of the viruses used in smallpox vaccination. Prior to the twentieth century, the method, source and origin of smallpox vaccinations remained unstandardised and opaque. We reconstruct and analyse viral vaccine genomes associated with smallpox vaccination from historical artefacts. Significantly, we recover viral molecules through non-destructive sampling of historical materials lacking signs of biological residues. We use the authenticated ancient genomes to reveal the evolutionary relationships of smallpox vaccination viruses within the poxviruses as a whole.

RevDate: 2020-07-19

Sheng G, Hu J, Tong H, et al (2020)

Ancient DNA of northern China Hystricidae sub-fossils reveals the evolutionary history of old world porcupines in the Late Pleistocene.

BMC evolutionary biology, 20(1):88 pii:10.1186/s12862-020-01656-x.

BACKGROUND: Old World porcupines (Family: Hystricidae) are the third-largest rodents and inhabit southern Europe, Asia, and most regions of Africa. They are a typical indicator of warm climate and their distribution is restricted to tropical and subtropical zones. In China, porcupines are widely distributed in southern areas of the Yangtze River. However, fossil remains have been identified in a few sites in northern China, among which Tianyuan Cave-near Zhoukoudian site-represents the latest known porcupine fossil record. So far, studies have focused mainly on porcupines' husbandry and domestication but little is known about their intrafamilial phylogenetic relationships and evolutionary history.

RESULTS: In this study, we sequence partial mitochondrial 12S rRNA and cyt b genes for seven Late Pleistocene porcupine individuals from Northern, Southern and Central China. Phylogenetic analyses show that the Tianyuan Cave porcupines, which had been morphologically identified as Hystrix subcristata, have a closer relationship to Hystrix brachyura.

CONCLUSION: Together with morphological adaptation characteristics, associated fauna, and climate change evidence, the molecular results reveal that a Late Quaternary extirpation has occurred during the evolutionary history of porcupines.

RevDate: 2020-07-17

Li J, Zarzar TG, White JD, et al (2020)

Robust genome-wide ancestry inference for heterogeneous datasets: illustrated using the 1,000 genome project with 3D facial images.

Scientific reports, 10(1):11850 pii:10.1038/s41598-020-68259-w.

Estimates of individual-level genomic ancestry are routinely used in human genetics, and related fields. The analysis of population structure and genomic ancestry can yield insights in terms of modern and ancient populations, allowing us to address questions regarding admixture, and the numbers and identities of the parental source populations. Unrecognized population structure is also an important confounder to correct for in genome-wide association studies. However, it remains challenging to work with heterogeneous datasets from multiple studies collected by different laboratories with diverse genotyping and imputation protocols. This work presents a new approach and an accompanying open-source toolbox that facilitates a robust integrative analysis for population structure and genomic ancestry estimates for heterogeneous datasets. We show robustness against individual outliers and different protocols for the projection of new samples into a reference ancestry space, and the ability to reveal and adjust for population structure in a simulated case-control admixed population. Given that visually evident and easily recognizable patterns of human facial characteristics co-vary with genomic ancestry, and based on the integration of three different sources of genome data, we generate average 3D faces to illustrate genomic ancestry variations within the 1,000 Genome project and for eight ancient-DNA profiles, respectively.

RevDate: 2020-07-17

Mizuno F, Taniguchi Y, Kondo O, et al (2020)

A study of 8,300-year-old Jomon human remains in Japan using complete mitogenome sequences obtained by next-generation sequencing.

Annals of human biology [Epub ahead of print].

Ancient human remains have been assigned to their mitochondrial DNA (mtDNA) haplogroups. To obtain efficiently deep and reliable nucleotide sequences of ancient DNA of interest, we achieved target enrichment followed by next-generation sequencing (NGS). Complete mitochondrial genome (mitogenome) sequences were obtained for three human remains from the Iyai rock-shelter site of the Initial Jomon Period in Japan. All the Jomon mitogenomes belong to haplogroup N9b, but no sequences among them were identical. High genetic diversity was clarified even among the Jomon human remains belonging to haplogroup N9b, which has been described as a haplogroup representing the Jomon people.

RevDate: 2020-07-15

Curry CJ, Davis BW, Bertola LD, et al (2020)

Spatiotemporal Genetic Diversity of Lions Reveals the Influence of Habitat Fragmentation Across Africa.

Molecular biology and evolution pii:5871931 [Epub ahead of print].

Direct comparisons between historical and contemporary populations allow for detecting changes in genetic diversity through time and assessment of the impact of habitat fragmentation. Here, we determined the genetic architecture of both historical and modern lions to document changes in genetic diversity over the last century. We surveyed microsatellite and mitochondrial genome variation from 143 high-quality museum specimens of known provenance, allowing us to directly compare this information with data from several recently published nuclear and mitochondrial studies. Our results provide evidence for male-mediated gene flow and recent isolation of local subpopulations, likely due to habitat fragmentation. Nuclear markers showed a significant decrease in genetic diversity from the historical (HE=0.833) to the modern (HE=0.796) populations, while mitochondrial genetic diversity was maintained (Hd = 0.98 for both). While the historical population appears to have been panmictic based on nDNA data, hierarchical structure analysis identified four tiers of genetic structure in modern populations and was able to detect most sampling locations. Mitogenome analyses identified 4 clusters: Southern, Mixed, Eastern, and Western; and were consistent between modern and historically sampled haplotypes. Within the last century, habitat fragmentation caused lion subpopulations to become more geographically isolated as human expansion changed the African landscape. This resulted in an increase in fine-scale nuclear genetic structure and loss of genetic diversity as lion subpopulations became more differentiated, while mitochondrial structure and diversity were maintained over time.

RevDate: 2020-07-15

Hallast P, Agdzhoyan A, Balanovsky O, et al (2020)

A Southeast Asian origin for present-day non-African human Y chromosomes.

Human genetics pii:10.1007/s00439-020-02204-9 [Epub ahead of print].

The genomes of present-day humans outside Africa originated almost entirely from a single out-migration ~ 50,000-70,000 years ago, followed by mixture with Neanderthals contributing ~ 2% to all non-Africans. However, the details of this initial migration remain poorly understood because no ancient DNA analyses are available from this key time period, and interpretation of present-day autosomal data is complicated due to subsequent population movements/reshaping. One locus, however, does retain male-specific information from this early period: the Y chromosome, where a detailed calibrated phylogeny has been constructed. Three present-day Y lineages were carried by the initial migration: the rare haplogroup D, the moderately rare C, and the very common FT lineage which now dominates most non-African populations. Here, we show that phylogenetic analyses of haplogroup C, D and FT sequences, including very rare deep-rooting lineages, together with phylogeographic analyses of ancient and present-day non-African Y chromosomes, all point to East/Southeast Asia as the origin 50,000-55,000 years ago of all known surviving non-African male lineages (apart from recent migrants). This observation contrasts with the expectation of a West Eurasian origin predicted by a simple model of expansion from a source near Africa, and can be interpreted as resulting from extensive genetic drift in the initial population or replacement of early western Y lineages from the east, thus informing and constraining models of the initial expansion.

RevDate: 2020-07-15

Iwasaki RL, Ishiya K, Kanzawa-Kiriyama H, et al (2020)

Evolutionary History of the Risk of SNPs for Diffuse-Type Gastric Cancer in the Japanese Population.

Genes, 11(7): pii:genes11070775.

A genome wide association study reported that the T allele of rs2294008 in a cancer-related gene, PSCA, is a risk allele for diffuse-type gastric cancer. This allele has the highest frequency (0.63) in Japanese in Tokyo (JPT) among 26 populations in the 1000 Genomes Project database. FST ≈ 0.26 at this single nucleotide polymorphism is one of the highest between JPT and the genetically close Han Chinese in Beijing (CHB). To understand the evolutionary history of the alleles in PSCA, we addressed: (i) whether the C non-risk allele at rs2294008 is under positive selection, and (ii) why the mainland Japanese population has a higher T allele frequency than other populations. We found that haplotypes harboring the C allele are composed of two subhaplotypes. We detected that positive selection on both subhaplotypes has occurred in the East Asian lineage. However, the selection on one of the subhaplotypes in JPT seems to have been relaxed or ceased after divergence from the continental population; this may have caused the elevation of T allele frequency. Based on simulations under the dual structure model (a specific demography for the Japanese) and phylogenetic analysis with ancient DNA, the T allele at rs2294008 might have had high frequency in the Jomon people (one of the ancestral populations of the modern Japanese); this may explain the high T allele frequency in the extant Japanese.

RevDate: 2020-07-14

Bongers JL, Nakatsuka N, O'Shea C, et al (2020)

Integration of ancient DNA with transdisciplinary dataset finds strong support for Inca resettlement in the south Peruvian coast.

Proceedings of the National Academy of Sciences of the United States of America pii:2005965117 [Epub ahead of print].

Ancient DNA (aDNA) analysis provides a powerful means of investigating human migration, social organization, and a plethora of other crucial questions about humanity's past. Recently, specialists have suggested that the ideal research design involving aDNA would include multiple independent lines of evidence. In this paper, we adopt a transdisciplinary approach integrating aDNA with archaeological, biogeochemical, and historical data to investigate six individuals found in two cemeteries that date to the Late Horizon (1400 to 1532 CE) and Colonial (1532 to 1825 CE) periods in the Chincha Valley of southern Peru. Genomic analyses indicate that these individuals are genetically most similar to ancient and present-day populations from the north Peruvian coast located several hundred kilometers away. These genomic data are consistent with 16th century written records as well as ceramic, textile, and isotopic data. These results provide some of the strongest evidence yet of state-sponsored resettlement in the pre-Colonial Andes. This study highlights the power of transdisciplinary research designs when using aDNA data and sets a methodological standard for investigating ancient mobility in complex societies.

RevDate: 2020-07-13

Mendes M, Alvim I, Borda V, et al (2020)

The history behind the mosaic of the Americas.

Current opinion in genetics & development, 62:72-77 pii:S0959-437X(20)30107-6 [Epub ahead of print].

Focusing on literature published in 2018-2020, we review inferences about: (i) how ancient DNA is contributing to clarify the peopling of the Americas and the dispersal of its first inhabitants, (ii) how the interplay between environmental diversity and culture has influenced the genetic structure and adaptation of Andean and Amazon populations, (iii) how genetics has contributed to our understanding of the Pre-Columbian Tupi expansion in Eastern South America, (iv) the subcontinental origins and dynamics of Post-Columbian admixture in the Americas, and finally, (v) episodes of adaptive natural selection in the American continent, particularly in the high altitudes of the Andes.

RevDate: 2020-07-12

Bai F, Zhang X, Ji X, et al (2020)

Paleolithic genetic link between Southern China and Mainland Southeast Asia revealed by ancient mitochondrial genomes.

Journal of human genetics pii:10.1038/s10038-020-0796-9 [Epub ahead of print].

The genetic history of Southern East Asians is not well-known, especially prior to the Neolithic period. To address this, we successfully sequenced two complete mitochondrial genomes of 11,000-year-old human individuals from Southern China, thus generating the oldest ancient DNA sequences from this area. Integrating published mitochondrial genomes, we characterized M71d, a new subhaplogroup of haplogroup M71. Our results suggest a possible early migration between Southern China and mainland Southeast Asia by at least 22,000 BP.

RevDate: 2020-07-11

Morrison J, McColl S, Louhelainen J, et al (2020)

Assessing the performance of quantity and quality metrics using the QIAGEN Investigator® Quantiplex® pro RGQ kit.

Science & justice : journal of the Forensic Science Society, 60(4):388-397.

The Quantiplex® Pro RGQ kit quantifies DNA in a sample, supports the detection of mixtures and assesses the extent of DNA degradation based on relative ratios of amplified autosomal and male markers. Data show no significant difference in the accuracy and sensitivity of quantification between this and the Promega PowerQuant® System, both detecting the lowest amount of DNA tested, 4 pg. Laboratory controlled mixed male:female DNA samples together with mock sexual assault samples were quantified across a range of mixture ratios. Analysis software detected mixed DNA samples across all ratios for both quantification kits. Subsequent STR analysis using the Investigator® 24Plex QS Kit was able to corroborate mixture detection down to 1:25 male:female DNA ratios, past which point mixtures appeared identical to single-source female samples. Analysis software also detected laboratory degraded DNA samples, with data showing a positive trend between the Degradation Index (DI) and length of time of sonication. When used on ancient remains the assay was able to triage samples for further analysis, and STR profiles were concordant with DNA quantification results in all instances. STR analyses of laboratory-controlled sensitivity, mixture, and degradation studies supports the quality metric obtained from quantification. These data support the use of the Quantiplex® Pro RGQ kit for sample screening and quantification in forensic casework and ancient DNA studies.

RevDate: 2020-07-10

Peyrégne S, K Prüfer (2020)

Present-Day DNA Contamination in Ancient DNA Datasets.

BioEssays : news and reviews in molecular, cellular and developmental biology [Epub ahead of print].

Present-day contamination can lead to false conclusions in ancient DNA studies. A number of methods are available to estimate contamination, which use a variety of signals and are appropriate for different types of data. Here an overview of currently available methods highlighting their strengths and weaknesses is provided, and a classification based on the signals used to estimate contamination is proposed. This overview aims at enabling researchers to choose the most appropriate methods for their dataset. Based on this classification, potential avenues for the further development of methods are discussed.

RevDate: 2020-07-10

Giuliani C, Franceschi C, Luiselli D, et al (2020)

Ecological Sensing Through Taste and Chemosensation Mediates Inflammation: A Biological Anthropological Approach.

Advances in nutrition (Bethesda, Md.) pii:5869586 [Epub ahead of print].

Ecological sensing and inflammation have evolved to ensure optima between organism survival and reproductive success in different and changing environments. At the molecular level, ecological sensing consists of many types of receptors located in different tissues that orchestrate integrated responses (immune, neuroendocrine systems) to external and internal stimuli. This review describes emerging data on taste and chemosensory receptors, proposing them as broad ecological sensors and providing evidence that taste perception is shaped not only according to sense epitopes from nutrients but also in response to highly diverse external and internal stimuli. We apply a biological anthropological approach to examine how ecological sensing has been shaped by these stimuli through human evolution for complex interkingdom communication between a host and pathological and symbiotic bacteria, focusing on population-specific genetic diversity. We then focus on how these sensory receptors play a major role in inflammatory processes that form the basis of many modern common metabolic diseases such as obesity, type 2 diabetes, and aging. The impacts of human niche construction and cultural evolution in shaping environments are described with emphasis on consequent biological responsiveness.

RevDate: 2020-07-09

Santiago E, Novo I, Pardiñas AF, et al (2020)

Recent demographic history inferred by high-resolution analysis of linkage disequilibrium.

Molecular biology and evolution pii:5869049 [Epub ahead of print].

Inferring changes in effective population size (Ne) in the recent past is of special interest for conservation of endangered species and for human history research. Current methods for estimating the very recent historical Ne are unable to detect complex demographic trajectories involving multiple episodes of bottlenecks, drops and expansions. We develop a theoretical and computational framework to infer the demographic history of a population within the past 100 generations from the observed spectrum of linkage disequilibrium (LD) of pairs of loci over a wide range of recombination rates in a sample of contemporary individuals. The cumulative contributions of all of the previous generations to the observed LD are included in our model, and a genetic algorithm is used to search for the sequence of historical Ne values that best explains the observed LD spectrum. The method can be applied from large samples to samples of fewer than 10 individuals using a variety of genotyping and DNA sequencing data: haploid, diploid with phased or unphased genotypes and pseudo-haploid data from low-coverage sequencing. The method was tested by computer simulation for sensitivity to genotyping errors, temporal heterogeneity of samples, population admixture and structural division into subpopulations, showing high tolerance to deviations from the assumptions of the model. Computer simulations also show that the proposed method outperforms other leading approaches when the inference concerns recent timeframes. Analysis of data from a variety of human and animal populations gave results in agreement with previous estimations by other methods or with records of historical events.

RevDate: 2020-07-08
CmpDate: 2020-07-08

Curry A (2020)

Incest in ancient Ireland suggests an elite ruled early farmers.

Science (New York, N.Y.), 368(6497):1299.

RevDate: 2020-07-07

Betti L, Beyer RM, Jones ER, et al (2020)

Climate shaped how Neolithic farmers and European hunter-gatherers interacted after a major slowdown from 6,100 BCE to 4,500 BCE.

Nature human behaviour pii:10.1038/s41562-020-0897-7 [Epub ahead of print].

The Neolithic transition in Europe was driven by the rapid dispersal of Near Eastern farmers who, over a period of 3,500 years, brought food production to the furthest corners of the continent. However, this wave of expansion was far from homogeneous, and climatic factors may have driven a marked slowdown observed at higher latitudes. Here, we test this hypothesis by assembling a large database of archaeological dates of first arrival of farming to quantify the expansion dynamics. We identify four axes of expansion and observe a slowdown along three axes when crossing the same climatic threshold. This threshold reflects the quality of the growing season, suggesting that Near Eastern crops might have struggled under more challenging climatic conditions. This same threshold also predicts the mixing of farmers and hunter-gatherers as estimated from ancient DNA, suggesting that unreliable yields in these regions might have favoured the contact between the two groups.

RevDate: 2020-07-04

Navarro-Romero MT, Muñoz ML, Alcala-Castañeda E, et al (2020)

A novel method of male sex identification of human ancient skeletal remains.

Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology pii:10.1007/s10577-020-09634-1 [Epub ahead of print].

Sex identification of ancient individuals is important to understand aspects of the culture, demographic structure, religious practices, disease association, and the history of the ancient civilizations. Sex identification is performed using anthropometric measurements and molecular genetics techniques, including quantification of the X and Y chromosomes. These approaches are not always reliable in subadult, or fragmented, incomplete skeletons or when the DNA is highly degraded. Most of the methods include the identification of the male and female sexes, but the absence of a specific marker for the males does not mean that the sample obtained was from a female. This study aims (1) to identify new male-specific regions that allow male identification; (2) to contrast the effectiveness of these markers against AMELX/AMELY and anthropometric measurement procedures; and (3) to test the efficacy of these markers in archaeological samples. For the first two aims, we used known sex samples, and for the third aim, we used samples from different archaeological sites. A novel molecular technique to identify male-specific regions by amplification of TTTY7, TSPY3, TTTY2, and TTTY22 genes of the human Y chromosome was developed. The results showed amplification of the specific DNA regions of Y chromosome in male individuals, with no amplification being observed in any of the female samples, confirming their specificity for male individuals. This approach complements the current procedures, such as the AMELX/AMELY test and anthropometric principle.

RevDate: 2020-07-03

Traversari M, Da Via S, Petrella E, et al (2020)

A case of dwarfism in 6th century Italy: Bioarchaeological assessment of a hereditary disorder.

OBJECTIVE: The skeletal remains of a short-statured individual (T17) are described and a differential diagnosis performed to determine the etiology of the condition.

MATERIALS: An individual considered pathologically short in stature was discovered in the burial site of Piazza XX Settembre, Modena (northern Italy).

METHODS: Morphological and morphometric analyses were performed, and T17 was compared to dwarfs from other localities and periods and to the adult female population from the same site. A paleopathological survey was undertaken to assess the degree of the skeletal elements of T17 were affected.

RESULTS: T17 was a female, 20-30 years of age at death, with a stature of 128 cm and disproportionate dwarfism associated with congenital skeletal dysplasia.

CONCLUSIONS: T17 likely affected by a form of hypochondroplasia.

SIGNIFICANCE: Anatomical consequences of hypochondroplasia are presented, and the timeframe and associated burial goods suggest a 6th-century Lombard short stature belonging to one of the earliest Lombard settlements in Italy.

Future genetic analysis would resolve if the mutation in the type 3 fibroblast growth factor receptor (FGFR3) is present in the remains of T17; however, it is not exclusivly linked to hypochondroplasia.

RevDate: 2020-07-01

Olalde I, C Posth (2020)

Latest trends in archaeogenetic research of west Eurasians.

Current opinion in genetics & development, 62:36-43 pii:S0959-437X(20)30072-1 [Epub ahead of print].

During the past ten years, archaeogenetic research has exponentially grown to study the genetic history of human populations, using genome-wide data from large numbers of ancient individuals. Of the entire globe, Europe and the Near East are the regions where ancient DNA data is by far most abundant with over 2500 genomes published at present. In this review, we focus on archaeological contexts that have received less attention in the literature, specifically those associated with west Eurasian hunter-gatherers as well as populations from the Iron Age and later historical periods. In addition, we emphasize a recent shift from continent-wide to regional and even site-specific studies, which is starting to provide novel insights into sociocultural aspects of past societies.

RevDate: 2020-06-30

Barquera R, J Krause (2020)

An ancient view on host pathogen interaction across time and space.

Current opinion in immunology, 65:65-69 pii:S0952-7915(20)30057-1 [Epub ahead of print].

The ancient DNA revolution provided diverse fields with an unprecedented opportunity to look back into the past and shed light on research aspects that were until now subject to speculation and inference from modern data. In particular enrichment methods that allow the targeted retrieval of millions of SNP positions from ancient human genomes, or even complete bacterial and viral genomes have the potential to revolutionize our understanding of host pathogen interactions. Ancient DNA combined with new bioinformatic tools now even allows actual allele calling for immunogenetic systems such as Human Leukocyte Antigen (HLA) across time and space. The coming years will provide us with frequency data of human immunity genes, such as HLA, as well as genome wide data of ancient pathogens from many time periods of human history, and will therefore provide us with a dynamic view on historical human adaptation to pathogen exposure on a population wide scale.

RevDate: 2020-06-29

Arning N, DJ Wilson (2020)

The past, present and future of ancient bacterial DNA.

Microbial genomics [Epub ahead of print].

Groundbreaking studies conducted in the mid-1980s demonstrated the possibility of sequencing ancient DNA (aDNA), which has allowed us to answer fundamental questions about the human past. Microbiologists were thus given a powerful tool to glimpse directly into inscrutable bacterial history, hitherto inaccessible due to a poor fossil record. Initially plagued by concerns regarding contamination, the field has grown alongside technical progress, with the advent of high-throughput sequencing being a breakthrough in sequence output and authentication. Albeit burdened with challenges unique to the analysis of bacteria, a growing number of viable sources for aDNA has opened multiple avenues of microbial research. Ancient pathogens have been extracted from bones, dental pulp, mummies and historical medical specimens and have answered focal historical questions such as identifying the aetiological agent of the black death as Yersinia pestis. Furthermore, ancient human microbiomes from fossilized faeces, mummies and dental plaque have shown shifts in human commensals through the Neolithic demographic transition and industrial revolution, whereas environmental isolates stemming from permafrost samples have revealed signs of ancient antimicrobial resistance. Culminating in an ever-growing repertoire of ancient genomes, the quickly expanding body of bacterial aDNA studies has also enabled comparisons of ancient genomes to their extant counterparts, illuminating the evolutionary history of bacteria. In this review we summarize the present avenues of research and contextualize them in the past of the field whilst also pointing towards questions still to be answered.

RevDate: 2020-06-26

Wang K, Goldstein S, Bleasdale M, et al (2020)

Ancient genomes reveal complex patterns of population movement, interaction, and replacement in sub-Saharan Africa.

Science advances, 6(24):eaaz0183.

Africa hosts the greatest human genetic diversity globally, but legacies of ancient population interactions and dispersals across the continent remain understudied. Here, we report genome-wide data from 20 ancient sub-Saharan African individuals, including the first reported ancient DNA from the DRC, Uganda, and Botswana. These data demonstrate the contraction of diverse, once contiguous hunter-gatherer populations, and suggest the resistance to interaction with incoming pastoralists of delayed-return foragers in aquatic environments. We refine models for the spread of food producers into eastern and southern Africa, demonstrating more complex trajectories of admixture than previously suggested. In Botswana, we show that Bantu ancestry post-dates admixture between pastoralists and foragers, suggesting an earlier spread of pastoralism than farming to southern Africa. Our findings demonstrate how processes of migration and admixture have markedly reshaped the genetic map of sub-Saharan Africa in the past few millennia and highlight the utility of combined archaeological and archaeogenetic approaches.

RevDate: 2020-06-26

Weiß CL, Gansauge MT, Aximu-Petri A, et al (2020)

Mining ancient microbiomes using selective enrichment of damaged DNA molecules.

BMC genomics, 21(1):432 pii:10.1186/s12864-020-06820-7.

BACKGROUND: The identification of bona fide microbial taxa in microbiomes derived from ancient and historical samples is complicated by the unavoidable mixture between DNA from ante- and post-mortem microbial colonizers. One possibility to distinguish between these sources of microbial DNA is querying for the presence of age-associated degradation patterns typical of ancient DNA (aDNA). The presence of uracils, resulting from cytosine deamination, has been detected ubiquitously in aDNA retrieved from diverse sources, and used as an authentication criterion. Here, we employ a library preparation method that separates molecules that carry uracils from those that do not for a set of samples that includes Neandertal remains, herbarium specimens and archaeological plant remains.

RESULTS: We show that sequencing DNA libraries enriched in molecules carrying uracils effectively amplifies age associated degradation patterns in microbial mixtures of ancient and historical origin. This facilitates the discovery of authentic ancient microbial taxa in cases where degradation patterns are difficult to detect due to large sequence divergence in microbial mixtures. Additionally, the relative enrichment of taxa in the uracil enriched fraction can help to identify bona fide ancient microbial taxa that could be missed using a more targeted approach.

CONCLUSIONS: Our experiments show, that in addition to its use in enriching authentic endogenous DNA of organisms of interest, the selective enrichment of damaged DNA molecules can be a valuable tool in the discovery of ancient microbial taxa.

RevDate: 2020-06-25

Kontopoulos I, Penkman K, Mullin VE, et al (2020)

Screening archaeological bone for palaeogenetic and palaeoproteomic studies.

PloS one, 15(6):e0235146 pii:PONE-D-20-01701.

The recovery and analysis of ancient DNA and protein from archaeological bone is time-consuming and expensive to carry out, while it involves the partial or complete destruction of valuable or rare specimens. The fields of palaeogenetic and palaeoproteomic research would benefit greatly from techniques that can assess the molecular quality prior to sampling. To be relevant, such screening methods should be effective, minimally-destructive, and rapid. This study reports results based on spectroscopic (Fourier-transform infrared spectroscopy in attenuated total reflectance [FTIR-ATR]; n = 266), palaeoproteomic (collagen content; n = 226), and palaeogenetic (endogenous DNA content; n = 88) techniques. We establish thresholds for three different FTIR indices, a) the infrared splitting factor [IRSF] that assesses relative changes in bioapatite crystals' size and homogeneity; b) the carbonate-to-phosphate [C/P] ratio as a relative measure of carbonate content in bioapatite crystals; and c) the amide-to-phosphate ratio [Am/P] for assessing the relative organic content preserved in bone. These thresholds are both extremely reliable and easy to apply for the successful and rapid distinction between well- and poorly-preserved specimens. This is a milestone for choosing appropriate samples prior to genomic and collagen analyses, with important implications for biomolecular archaeology and palaeontology.

RevDate: 2020-06-23

Mathov Y, Batyrev D, Meshorer E, et al (2020)

Harnessing epigenetics to study human evolution.

Current opinion in genetics & development, 62:23-29 pii:S0959-437X(20)30074-5 [Epub ahead of print].

Recent advances in ancient DNA extraction and high-throughput sequencing technologies enabled the high-quality sequencing of archaic genomes, including the Neanderthal and the Denisovan. While comparisons with modern humans revealed both archaic-specific and human-specific sequence changes, in the absence of gene expression information, understanding the functional implications of such genetic variations remains a major challenge. To study gene regulation in archaic humans, epigenetic research comes to our aid. DNA methylation, which is highly correlated with transcription, can be directly measured in modern samples, as well as reconstructed in ancient samples. This puts DNA methylation as a natural basis for comparative epigenetics between modern humans, archaic humans and nonhuman primates.

RevDate: 2020-06-23

Adrion JR, Cole CB, Dukler N, et al (2020)

A community-maintained standard library of population genetic models.

eLife, 9: pii:54967 [Epub ahead of print].

The explosion in population genomic data demands ever more complex modes of analysis, and increasingly these analyses depend on sophisticated simulations. Re-cent advances in population genetic simulation have made it possible to simulate large and complex models, but specifying such models for a particular simulation engine remains a difficult and error-prone task. Computational genetics researchers currently re-implement simulation models independently, leading to inconsistency and duplication of effort. This situation presents a major barrier to empirical researchers seeking to use simulations for power analyses of upcoming studies or sanity checks on existing genomic data. Population genetics, as a field, also lacks standard benchmarks by which new tools for inference might be measured. Here we describe a new resource, stdpopsim, that attempts to rectify this situation. Stdpopsim is a community-driven open source project, which provides easy access to a growing catalog of published simulation models from a range of organisms and supports multiple simulation engine backends. This resource is available as a well-documented python library with a simple command-line interface. We share some examples demonstrating how stdpopsim can be used to systematically compare demographic inference methods, and we encourage a broader community of developers to contribute to this growing resource.

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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.

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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.

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