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More than two hundred papers have reported genome-wide data from ancient humans. While the raw data for the vast majority are fully publicly available testifying to the commitment of the paleogenomics community to open data, formats for both raw data and meta-data differ. There is thus a need for uniform curation and a centralized, version-controlled compendium that researchers can download, analyze, and reference. Since 2019, we have been maintaining the Allen Ancient DNA Resource (AADR), which aims to provide an up-to-date, curated version of the world’s published ancient human DNA data, represented at more than a million single nucleotide polymorphisms (SNPs) at which almost all ancient individuals have been assayed. The AADR has gone through six public releases since it first was made available and crossed the threshold of >10,000 ancient individuals with genome-wide data at the end of 2022. This note is intended as a citable description of the AADR.

Acknowledgements: The authors thank G. Marciani and O. Jöris for comments on archaeology; C. Jeong, M. Spyrou and K. Prüfer for comments on genetics; M. O’Reilly for graphical support for Fig. 5 and Extended Data Fig. 9; the entire IT and laboratory teams at the Department of Archaeogenetics of MPI-SHH for technical assistance; M. Meyer and S. Nagel for support with single-stranded library preparation; K. Post, P. van Es, J. Glimmerveen, M. Medendorp, M. Sier, S. Dikstra, M. Dikstra, R. van Eerden, D. Duineveld and A. Hoekman for providing access to human specimens from the North Sea (The Netherlands); M. D. Garralda and A. Estalrrich for providing access to human specimens from La Riera (Spain); J. Górski and M. Zając for providing access to human specimens from Maszycka cave; C. Di Patti for providing access to human specimens from San Teodoro 2 (Italy); P. Blaževičius for providing access to the Donkalnis human remains and the new radiocarbon dates; the Italian Ministry of Culture and Soprintendenza Archeologia Belle Arti e Paesaggio for the Provinces of Verona, Rovigo, and Vicenza for granting access to the human remains of Tagliente 2; F. Fontana, who carries out investigations of the Riparo Tagliente site (Italy); the Friuli Venezia Giulia Superintendency for providing access to the human tooth Pradis 1; and the Soprintendenza Archeologia Belle Arti e Paesaggio for the Provinces of Barletta-Andria-Trani and Foggia for providing access to the Paglicci human remains. This project has received funding by the European Research Council under the European Union’s Horizon 2020 research and innovation programme under grant agreements no. 803147-RESOLUTION (to S.T.), no. 771234-PALEoRIDER (to W.H.), no. 864358 (to K.M.), no. 724703 and no. 101019659 (to K.H.). K.H. is also supported by the Deutsche Forschungsgemeinschaft (DFG FOR 2237). E.A. has received funding from the Van de Kamp fonds. PACEA co-authors of this research benefited from the scientific framework of the University of Bordeaux’s IdEx Investments for the Future programme/GPR Human Past. A.G.-O. is supported by a Ramón y Cajal fellowship (RYC-2017-22558). L. Sineo, M.L. and D.C. have received funding from the Italian Ministry of University and Research (MUR) PRIN 2017 grants 20177PJ9XF and 20174BTC4R_002. H. Rougier received support from the College of Social and Behavioral Sciences of CSUN and the CSUN Competition for RSCA Awards. C.L.S. and T. Saupe received support from the European Union through the European Regional Development Fund (project no. 2014-2020.4.01.16-0030) and C.L.S. received support from the Estonian Research Council grant PUT (PRG243). S. Shnaider received support from the Russian Science Foundation (no. 19-78-10053)., Modern humans have populated Europe for more than 45,000 years1,2. Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period3. Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe4, but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants.

Long DNA sequences shared between two individuals, known as Identical by descent (IBD) segments, are a powerful signal for identifying close and distant biological relatives because they only arise when the pair shares a recent common ancestor. Existing methods to call IBD segments between present-day genomes cannot be straightforwardly applied to ancient DNA data (aDNA) due to typically low coverage and high genotyping error rates. We present ancIBD, a method to identify IBD segments for human aDNA data implemented as a Python package. Our approach is based on a Hidden Markov Model, using as input genotype probabilities imputed based on a modern reference panel of genomic variation. Through simulation and downsampling experiments, we demonstrate that ancIBD robustly identifies IBD segments longer than 8 centimorgan for aDNA data with at least either 0.25x average whole-genome sequencing (WGS) coverage depth or at least 1x average depth for in-solution enrichment experiments targeting a widely used aDNA SNP set (‘1240k’). This application range allows us to screen a substantial fraction of the aDNA record for IBD segments and we showcase two downstream applications. First, leveraging the fact that biological relatives up to the sixth degree are expected to share multiple long IBD segments, we identify relatives between 10,156 ancient Eurasian individuals and document evidence of long-distance migration, for example by identifying a pair of two approximately fifth-degree relatives who were buried 1410km apart in Central Asia 5000 years ago. Second, by applying ancIBD, we reveal new details regarding the spread of ancestry related to Steppe pastoralists into Europe starting 5000 years ago. We find that the first individuals in Central and Northern Europe carrying high amounts of Steppe-ancestry, associated with the Corded Ware culture, share high rates of long IBD (12-25 cM) with Yamnaya herders of the Pontic-Caspian steppe, signaling a strong bottleneck and a recent biological connection on the order of only few hundred years, providing evidence that the Yamnaya themselves are a main source of Steppe ancestry in Corded Ware people. We also detect elevated sharing of long IBD segments between Corded Ware individuals and people associated with the Globular Amphora culture (GAC) from Poland and Ukraine, who were Copper Age farmers not yet carrying Steppe-like ancestry. These IBD links appear for all Corded Ware groups in our analysis, indicating that individuals related to GAC contexts must have had a major demographic impact early on in the genetic admixtures giving rise to various Corded Ware groups across Europe. These results show that detecting IBD segments in aDNA can generate new insights both on a small scale, relevant to understanding the life stories of people, and on the macroscale, relevant to large-scale cultural-historical events.

Growing reliance on animal and plant domestication in the Near East and beyond during the Pre-Pottery Neolithic B (PPNB) (the ninth to eighth millennium BC) has often been associated with a “revolutionary” social transformation from mobility toward more sedentary lifestyles. We are able to yield nuanced insights into the process of the Neolithization in the Near East based on a bioarchaeological approach integrating isotopic and archaeogenetic analyses on the bone remains recovered from Nevalı Çori, a site occupied from the early PPNB in Turkey where some of the earliest evidence of animal and plant domestication emerged, and from Ba'ja, a typical late PPNB site in Jordan. In addition, we present the archaeological sequence of Nevalı Çori together with newly generated radiocarbon dates. Our results are based on strontium ( 87 Sr/ 86 Sr), carbon, and oxygen (δ 18 O and δ 13 C carb ) isotopic analyses conducted on 28 human and 29 animal individuals from the site of Nevalı Çori. 87 Sr/ 86 Sr results indicate mobility and connection with the contemporaneous surrounding sites during the earlier PPNB prior to an apparent decline in this mobility at a time of growing reliance on domesticates. Genome-wide data from six human individuals from Nevalı Çori and Ba'ja demonstrate a diverse gene pool at Nevalı Çori that supports connectedness within the Fertile Crescent during the earlier phases of Neolithization and evidence of consanguineous union in the PPNB Ba'ja and the Iron Age Nevalı Çori.

The Neolithic and Bronze Ages were highly transformative periods for the genetic history of Europe but for the Aegean—a region fundamental to Europe’s prehistory—the biological dimensions of cultural transitions have been elucidated only to a limited extent so far. We have analysed newly generated genome-wide data from 102 ancient individuals from Crete, the Greek mainland and the Aegean Islands, spanning from the Neolithic to the Iron Age. We found that the early farmers from Crete shared the same ancestry as other contemporaneous Neolithic Aegeans. In contrast, the end of the Neolithic period and the following Early Bronze Age were marked by ‘eastern’ gene flow, which was predominantly of Anatolian origin in Crete. Confirming previous findings for additional Central/Eastern European ancestry in the Greek mainland by the Middle Bronze Age, we additionally show that such genetic signatures appeared in Crete gradually from the seventeenth to twelfth centuries bc, a period when the influence of the mainland over the island intensified. Biological and cultural connectedness within the Aegean is also supported by the finding of consanguineous endogamy practiced at high frequencies, unprecedented in the global ancient DNA record. Our results highlight the potential of archaeogenomic approaches in the Aegean for unravelling the interplay of genetic admixture, marital and other cultural practices. Results - The archaeogenetic dataset - Transregional genetic entanglements of Aegean populations - Neolithic to Early/Middle Bronze Age - Mobility in the Middle/Late Bronze Age Aegean - Insights into sex bias, biological kinship and marital practices Discussion Methods - Preparation of aDNA analysis - Analysis of population structure - Admixture analysis with ADMIXTOOLS - Admixture dating - Analysis of biological relatedness - Analysis of ROH - Direct AMS radiocarbon dating

SummaryThe timing of the initial peopling of the Polynesian islands remains highly debated. Suggested dates are primarily based on archaeological evidence and differ by several hundred years. Ioannidis et al. [2021] used genome-wide data from 430 modern individuals from 21 Pacific islands to obtain genetic estimates. Their results supported late settlement dates, e.g. approximately 1200 CE for Rapa Nui. However, when investigating the underlying model we found that the genetic estimator used by Ioannidis et al. [2021] is biased to be about 300 years too old. Correcting for this bias gives genetic settlement dates that are more recent than any dates consistent with archaeological records, as radiocarbon dating of human-modified artifacts shows settlement definitively earlier than the bias-corrected genetic estimates. These too-recent estimates can only be explained by substantial gene flow between islands after their initial settlements. Therefore, contacts attested by archaeological and linguistic evidence [Kirch, 2021] must have been accompanied also by demographically significant movement of people. This gene flow well after the initial settlements was not modelled by Ioannidis et al. [2021] and challenges their interpretation that carving anthropomorphic stone statues was spread during initial settlements of islands. Instead, the distribution of this cultural practice likely reflects later inter-island exchanges, as suggested earlier [Kirch, 2017].

Trade and colonization caused an unprecedented increase in Mediterranean human mobility in the first millennium BCE. Often seen as a dividing force, warfare is in fact another catalyst of culture contact. We provide insight into the demographic dynamics of ancient warfare by reporting genome-wide data from fifth-century soldiers who fought for the army of the Greek Sicilian colony of Himera, along with representatives of the civilian population, nearby indigenous settlements, and 96 present-day individuals from Italy and Greece. Unlike the rest of the sample, many soldiers had ancestral origins in northern Europe, the Steppe, and the Caucasus. Integrating genetic, archaeological, isotopic, and historical data, these results illustrate the significant role mercenaries played in ancient Greek armies and highlight how participation in war contributed to continental-scale human mobility in the Classical world.

Donkeys transformed human history as essential beasts of burden for long-distance movement, especially across semi-arid and upland environments. They remain insufficiently studied despite globally expanding and providing key support to low- to middle-income communities. To elucidate their domestication history, we constructed a comprehensive genome panel of 207 modern and 31 ancient donkeys, as well as 15 wild equids. We found a strong phylogeographic structure in modern donkeys that supports a single domestication in Africa similar to 5000 BCE, followed by further expansions in this continent and Eurasia and ultimately returning to Africa. We uncover a previously unknown genetic lineage in the Levant similar to 200 BCE, which contributed increasing ancestry toward Asia. Donkey management involved inbreeding and the production of giant bloodlines at a time when mules were essential to the Roman economy and military. French National Research Agency (ANR) ANR-10-INBS-09 info:eu-repo/semantics/publishedVersion

Motivation Human ancient DNA (aDNA) studies have surged in recent years, revolutionizing the study of the human past. Typically, aDNA is preserved poorly, making such data prone to contamination from other human DNA. Therefore, it is important to rule out substantial contamination before proceeding to downstream analysis. As most aDNA samples can only be sequenced to low coverages ( Results We present a new method to estimate contamination in aDNA for male modern humans. It utilizes a Li&Stephens haplotype copying model for haploid X chromosomes, with mismatches modeled as errors or contamination. We assessed this new approach, hapCon, on simulated and down-sampled empirical aDNA data. Our experiments demonstrate that hapCon outperforms a commonly used tool for estimating male X contamination (ANGSD), with substantially lower variance and narrower confidence intervals, especially in the low coverage regime. We found that hapCon provides useful contamination estimates for coverages as low as 0.1× for SNP capture data (1240k) and 0.02× for whole genome sequencing data, substantially extending the coverage limit of previous male X chromosome-based contamination estimation methods. Our experiments demonstrate that hapCon has little bias for contamination up to 25–30% as long as the contaminating source is specified within continental genetic variation, and that its application range extends to human aDNA as old as ∼45 000 and various global ancestries. Availability and implementation We make hapCon available as part of a python package (hapROH), which is available at the Python Package Index (https://pypi.org/project/hapROH) and can be installed via pip. The documentation provides example use cases as blueprints for custom applications (https://haproh.readthedocs.io/en/latest/hapCon.html). The program can analyze either BAM files or pileup files produced with samtools. An implementation of our software (hapCon) using Python and C is deposited at https://github.com/hyl317/hapROH. Supplementary information Supplementary data are available at Bioinformatics online.

We report genome-wide data for 33 Ashkenazi Jews (AJ), dated to the 14th century, following a salvage excavation at the medieval Jewish cemetery of Erfurt, Germany. The Erfurt individuals are genetically similar to modern AJ and have substantial Southern European ancestry, but they show more variability in Eastern European-related ancestry than modern AJ. A third of the Erfurt individuals carried the same nearly-AJ-specific mitochondrial haplogroup and eight carried pathogenic variants known to affect AJ today. These observations, together with high levels of runs of homozygosity, suggest that the Erfurt community had already experienced the major reduction in size that affected modern AJ. However, the Erfurt bottleneck was more severe, implying substructure in medieval AJ. Together, our results suggest that the AJ founder event and the acquisition of the main sources of ancestry pre-dated the 14th century and highlight late medieval genetic heterogeneity no longer present in modern AJ.

We report genome-wide data from 33 Ashkenazi Jews (AJ), dated to the 14

L’exploration des structures de parenté dans les sociétés du passé a été au centre des études en archéologie et en anthropologie. Cependant, la reconstruction des liens de parenté biologique en contextes archéologiques a rarement été accessible. Avec le développement des méthodes d’analyses en ADN ancien, il est désormais possible d’obtenir des données génomiques pour de nombreux individus d’un même groupe, même dans le cas d’une faible conservation de l’ADN. Nous présentons ici de nouvelles ...

Present-day people from England and Wales have more ancestry derived from early European farmers (EEF) than did people of the Early Bronze Age1. To understand this, here we generated genome-wide data from 793 individuals, increasing data from the Middle to the Late Bronze Age and Iron Age in Britain by 12-fold, and western and central Europe by 3.5-fold. Between 1000 and 875 BC, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of people of England and Wales from the Iron Age, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to the Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and the independent genetic trajectory in Britain is also reflected in the rise of the allele conferring lactase persistence to approximately 50% by this time compared to approximately 7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period., This work was funded in part by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 834087; the COMMIOS Project to I.A.). M.N. was supported by the Croatian Science Fund grant (HRZZ IP-2016-06-1450). P.V., M.Dobeš and Z.V. were supported by the Ministry of Culture of the Czech Republic (DKRVO 2019-2023/7.I.c, 00023272). M.E. was supported by Czech Academy of Sciences award Praemium Academiae. M.Dobisíková and A.Danielisová were supported by the grant RVO 67985912 of the Institute of Archaeology of the Czech Academy of Sciences. M.G.B.F. was funded by The Leverhulme Trust via a Doctoral Scholarship scheme awarded to M.Pala and M.B.R. Support to M.Legge came from the South, West & Wales Doctoral Training Partnership. M.G.’s osteological analyses were funded by Culture Vannin. A.S.-N. was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. T.H., T.S. and K.K.’s work was supported by a grant from the Hungarian Research, Development and Innovation Office (project number: FK128013). We acknowledge support for radiocarbon dating and stable isotope analyses as well as access to skeletal material from Manx National Heritage and A. Fox. Dating analysis was funded by Leverhulme Trust grant RPG-388. M.G.T. and I.B. were supported by a Wellcome Trust Investigator Award (project 100713/Z/12/Z). I.O. was supported by a Ramón y Cajal grant from Ministerio de Ciencia e Innovación, Spanish Government (RYC2019-027909-I). The research directed at Harvard was funded by NIH grants GM100233 and HG012287, by John Templeton Foundation grant 61220, by a gift from Jean-François Clin, and by the Allen Discovery Center program, a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation. D.R. is also an Investigator of the Howard Hughes Medical Institute.

Relatively little is known about Nubia’s genetic landscape prior to the influence of the Islamic migrations that began in the late 1st millennium CE. Here, we increase the number of ancient individuals with genome-level data from the Nile Valley from three to 69, reporting data for 66 individuals from two cemeteries at the Christian Period (~650–1000 CE) site of Kulubnarti, where multiple lines of evidence suggest social stratification. The Kulubnarti Nubians had ~43% Nilotic-related ancestry (individual variation between ~36–54%) with the remaining ancestry consistent with being introduced through Egypt and ultimately deriving from an ancestry pool like that found in the Bronze and Iron Age Levant. The Kulubnarti gene pool – shaped over a millennium – harbors disproportionately female-associated West Eurasian-related ancestry. Genetic similarity among individuals from the two cemeteries supports a hypothesis of social division without genetic distinction. Seven pairs of inter-cemetery relatives suggest fluidity between cemetery groups. Present-day Nubians are not directly descended from the Kulubnarti Nubians, attesting to additional genetic input since the Christian Period., Little is known about the genetic landscape of people living in the Nile region prior to the Islamic migrations of the late 1st millennium CE. Here, the authors report genome-wide data for 66 ancient individuals to investigate the genetic ancestry of a Christian Period group from Kulubnarti.

Neandertal DNA makes up 2–3% of the genomes of all non-African individuals. The patterns of Neandertal ancestry in modern humans have been used to estimate that this is the result of gene flow that occurred during the expansion of modern humans into Eurasia, but the precise dates of this event remain largely unknown. Here, we introduce an extended admixture pulse model that allows joint estimation of the timing and duration of gene flow. This model leads to simple expressions for both the admixture segment distribution and the decay curve of ancestry linkage disequilibrium, and we show that these two statistics are closely related. In simulations, we find that estimates of the mean time of admixture are largely robust to details in gene flow models, but that the duration of the gene flow can only be recovered if gene flow is very recent and the exact recombination map is known. These results imply that gene flow from Neandertals into modern humans could have happened over hundreds of generations. Ancient genomes from the time around the admixture event are thus likely required to resolve the question when, where, and for how long humans and Neandertals interacted.

Humans settled the Caribbean about 6,000 years ago, and ceramic use and intensified agriculture mark a shift from the Archaic to the Ceramic Age at around 2,500 years ago1,2,3. Here we report genome-wide data from 174 ancient individuals from The Bahamas, Haiti and the Dominican Republic (collectively, Hispaniola), Puerto Rico, Curaçao and Venezuela, which we co-analysed with 89 previously published ancient individuals. Stone-tool-using Caribbean people, who first entered the Caribbean during the Archaic Age, derive from a deeply divergent population that is closest to Central and northern South American individuals; contrary to previous work4, we find no support for ancestry contributed by a population related to North American individuals. Archaic-related lineages were >98% replaced by a genetically homogeneous ceramic-using population related to speakers of languages in the Arawak family from northeast South America; these people moved through the Lesser Antilles and into the Greater Antilles at least 1,700 years ago, introducing ancestry that is still present. Ancient Caribbean people avoided close kin unions despite limited mate pools that reflect small effective population sizes, which we estimate to be a minimum of 500–1,500 and a maximum of 1,530–8,150 individuals on the combined islands of Puerto Rico and Hispaniola in the dozens of generations before the individuals who we analysed lived. Census sizes are unlikely to be more than tenfold larger than effective population sizes, so previous pan-Caribbean estimates of hundreds of thousands of people are too large5,6. Confirming a small and interconnected Ceramic Age population7, we detect 19 pairs of cross-island cousins, close relatives buried around 75 km apart in Hispaniola and low genetic differentiation across islands. Genetic continuity across transitions in pottery styles reveals that cultural changes during the Ceramic Age were not driven by migration of genetically differentiated groups from the mainland, but instead reflected interactions within an interconnected Caribbean world1,8., This work was supported by a grant from the National Geographic Society to M. Pateman to facilitate analysis of skeletal material from The Bahamas and by a grant from the Italian ‘Ministry of Foreign Affairs and International Cooperation’ (Italian archaeological, anthropological and ethnological missions abroad, DGPSP Ufficio VI). D.R. was funded by NSF HOMINID grant BCS-1032255, NIH (NIGMS) grant GM100233, the Paul Allen Foundation, the John Templeton Foundation grant 61220 and the Howard Hughes Medical Institute.

Present-day Tibetans have adapted both genetically and culturally to the high altitude environment of the Tibetan Plateau, but fundamental questions about their origins remain unanswered. Recent archaeological and genetic research suggests the presence of an early population on the Plateau within the past 40 thousand years, followed by the arrival of subsequent groups within the past 10 thousand years. Here, we obtain new genome-wide data for 33 ancient individuals from high elevation sites on the southern fringe of the Tibetan Plateau in Nepal, who we show are most closely related to present-day Tibetans. They derive most of their ancestry from groups related to Late Neolithic populations at the northeastern edge of the Tibetan Plateau but also harbor a minor genetic component from a distinct and deep Paleolithic Eurasian ancestry. In contrast to their Tibetan neighbors, present-day non-Tibetan Tibeto-Burman speakers living at mid-elevations along the southern and eastern margins of the Plateau form a genetic cline that reflects a distinct genetic history. Finally, a comparison between ancient and present-day highlanders confirms ongoing positive selection of high altitude adaptive alleles.

Paleogenomic and bioanthropological studies of ancient massacres have highlighted sites where the victims were male and plausibly died all in battle, or were executed members of the same family as might be expected from a killing intentionally directed at subsets of a community, or where the massacred individuals were plausibly members of a migrant community in conflict with previously established groups, or where there was evidence that the killing was part of a religious ritual. Here we provide evidence of killing on a massive scale in prehistory that was not directed to a specific family, based on genome-wide ancient DNA for 38 of the 41 documented victims of a 6,200 year old massacre in Potočani, Croatia and combining our results with bioanthropological data. We highlight three results: (i) the majority of individuals were unrelated and instead were a sample of what was clearly a large farming population, (ii) the ancestry of the individuals was homogenous which makes it unlikely that the massacre was linked to the arrival of new genetic ancestry, and (iii) there were approximately equal numbers of males and females. Combined with the bioanthropological evidence that the victims were of a wide range of ages, these results show that large-scale indiscriminate killing is a horror that is not just a feature of the modern and historic periods, but was also a significant process in pre-state societies., M.N., I.J. and J.B. were supported by the Croatian Science Fund grant HRZZ IP-2016-06-1450. I.O. was supported by a fellowship from ”la Caixa” Foundation (ID 100010434), code LCF/BQ/PI19/11690004. D.R. was supported by the National Institutes of Health (NIGMS GM100233), the John Templeton Foundation (grant 61220), and the Paul Allen Foundation (Allen Discovery Center grant), and is an Investigator of the Howard Hughes Medical Institute. The ancient DNA work was funded by NIH (NIGMS) grant GM100233, the Paul Allen Foundation, the John Templeton Foundation grant 61220 and the Howard Hughes Medical Institute.

Parental relatedness of present-day humans varies substantially across the globe, but little is known about the past. Here we analyze ancient DNA, leveraging that parental relatedness leaves genomic traces in the form of runs of homozygosity. We present an approach to identify such runs in low-coverage ancient DNA data aided by haplotype information from a modern phased reference panel. Simulation and experiments show that this method robustly detects runs of homozygosity longer than 4 centimorgan for ancient individuals with at least 0.3 × coverage. Analyzing genomic data from 1,785 ancient humans who lived in the last 45,000 years, we detect low rates of first cousin or closer unions across most ancient populations. Moreover, we find a marked decay in background parental relatedness co-occurring with or shortly after the advent of sedentary agriculture. We observe this signal, likely linked to increasing local population sizes, across several geographic transects worldwide., Little is known about how human parental relatedness varied across ancient populations. Runs of homozygosity (ROH) in the offspring’s genome can give clues. Here, the authors present a method to identify ROH in ancient genomes and infer low rates of close kin unions across most ancient populations.

At present day, human parental relatedness varies substantially across the globe, but little is known about the past. Here we use ancient DNA to provide new insights, leveraging that parental relatedness leaves traces in the offspring’s genome in the form of runs of homozygosity. We present a method to identify such runs in low-coverage ancient DNA data using linkage information from a reference panel of modern haplotypes. As a result, the method facilitates analysis of a much larger fraction of the global ancient DNA record than previously possible. Simulation and experiments show that this new method has power to detect runs of homozygosity longer than 4 centimorgan for ancient individuals with at least 0.3× coverage. We used this new method to analyze sequence data from 1,785 humans from the last 45,000 years. Generally, we detect very low rates of first cousin or closer unions across most ancient populations. Moreover, our results evidence a substantial impact of the adoption of agricultural lifestyles: We find a marked decay in background parental relatedness, co-occurring with or shortly after the advent of sedentary agriculture. We observe this signal, likely linked to increasing local population sizes, across several geographic regions worldwide.

Humans settled the Caribbean ~6,000 years ago, with intensified agriculture and ceramic use marking a shift from the Archaic Age to the Ceramic Age ~2,500 years ago. To shed new light on the history of Caribbean people, we report genome-wide data from 184 individuals predating European contact from The Bahamas, Cuba, Hispaniola, Puerto Rico, Curaçao, and northwestern Venezuela. A largely homogeneous ceramic-using population most likely originating in northeastern South America and related to present-day Arawak-speaking groups moved throughout the Caribbean at least 1,800 years ago, spreading ancestry that is still detected in parts of the region today. These people eventually almost entirely replaced Archaic-related lineages in Hispaniola but not in northwestern Cuba, where unadmixed Archaic-related ancestry persisted into the last millennium. We document high mobility and inter-island connectivity throughout the Ceramic Age as reflected in relatives buried ~75 kilometers apart in Hispaniola and low genetic differentiation across many Caribbean islands, albeit with subtle population structure distinguishing the Bahamian islands we studied from the rest of the Caribbean and from each other, and long-term population continuity in southeastern coastal Hispaniola differentiating this region from the rest of the island. Ceramic-associated people avoided close kin unions despite limited mate pools reflecting low effective population sizes (2Ne=1000-2000) even at sites on the large Caribbean islands. While census population sizes can be an order of magnitude larger than effective population sizes, pan-Caribbean population size estimates of hundreds of thousands are likely too large. Transitions in pottery styles show no evidence of being driven by waves of migration of new people from mainland South America; instead, they more likely reflect the spread of ideas and people within an interconnected Caribbean world.

Ringbauer et al. introduce a novel method to estimate barriers to gene flow in a two-dimensional population. Their inference scheme utilizes geographically... In continuous populations with local migration, nearby pairs of individuals have on average more similar genotypes than geographically well-separated pairs. A barrier to gene flow distorts this classical pattern of isolation by distance. Genetic similarity is decreased for sample pairs on different sides of the barrier and increased for pairs on the same side near the barrier. Here, we introduce an inference scheme that uses this signal to detect and estimate the strength of a linear barrier to gene flow in two dimensions. We use a diffusion approximation to model the effects of a barrier on the geographic spread of ancestry backward in time. This approach allows us to calculate the chance of recent coalescence and probability of identity by descent. We introduce an inference scheme that fits these theoretical results to the geographic covariance structure of bialleleic genetic markers. It can estimate the strength of the barrier as well as several demographic parameters. We investigate the power of our inference scheme to detect barriers by applying it to a wide range of simulated data. We also showcase an example application to an Antirrhinum majus (snapdragon) flower-color hybrid zone, where we do not detect any signal of a strong genome-wide barrier to gene flow.

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.

Recent ancient DNA studies of western Eurasia have revealed a dynamic history of admixture, with evidence for major migrations during the Neolithic and Bronze Age. The population of the Mediterranean island of Sardinia has been notable in these studies –} Neolithic individuals from mainland Europe cluster more closely with Sardinian individuals than with all other present-day Europeans. The current model to explain this result is that Sardinia received an initial influx of Neolithic ancestry and then remained relatively isolated from expansions in the later Neolithic and Bronze Age that took place in continental Europe. To test this model, we generated genome-wide capture data (approximately 1.2 million variants) for 43 ancient Sardinian individuals spanning the Neolithic through the Bronze Age, including individuals from Sardinia{’}s Nuragic culture, which is known for the construction of numerous large stone towers throughout the island. We analyze these new samples in the context of previously generated genome-wide ancient DNA data from 972 ancient individuals across western Eurasia and whole-genome sequence data from approximately 1,500 modern individuals from Sardinia. The ancient Sardinian individuals show a strong affinity to western Mediterranean Neolithic populations and we infer a high degree of genetic continuity on the island from the Neolithic (around fifth millennium BCE) through the Nuragic period (second millennium BCE). In particular, during the Bronze Age in Sardinia, we do not find significant levels of the {“}Steppe{” ancestry that was spreading in many other parts of Europe at that time. We also characterize subsequent genetic influx between the Nuragic period and the present. We detect novel, modest signals of admixture between 1,000 BCE and present-day, from ancestry sources in the eastern and northern Mediterranean. Within Sardinia, we confirm that populations from the more geographically isolated mountainous provinces have experienced elevated levels of genetic drift and that northern and southwestern regions of the island received more gene flow from outside Sardinia. Overall, our genetic analysis sheds new light on the origin of Neolithic settlement on Sardinia, reinforces models of genetic continuity on the island, and provides enhanced power to detect post-Bronze-Age gene flow. Together, these findings offer a refined demographic model for future medical genetic studies in Sardinia. Introduction Results - Ancient DNA from Sardinia - Uniparentally inherited markers - Results from genome-wide aDNA - Similarity to western mainland Neolithic populations - Constancy of Western Hunter Gatherer ancestry - Continuity from the Sardinian Neolithic through the Nuragic - From the Nuragic to present-day Sardinia - Fine-scale structure in contemporary Sardinia Discussion Materials and Methods - Archaeological sampling - Initial sample screening and sequencing - Merging newly generated data with published data - Principal Components Analysis - ADMIXTURE Analysis - Estimation of f-statistics - Estimation of FST -coefficients - Estimation of admixture proportions with qpAdm - Inference of Y haplogroups

In continuous populations with local migration, nearby pairs of individuals have on average more similar genotypes than geographically well separated pairs. A barrier to gene flow distorts this classical pattern of isolation by distance. Genetic similarity is decreased for sample pairs on different sides of the barrier and increased for pairs on the same side near the barrier. Here, we introduce an inference scheme that utilizes this signal to detect and estimate the strength of a linear barrier to gene flow in two-dimensions. We use a diffusion approximation to model the effects of a barrier on the geographical spread of ancestry backwards in time. This approach allows us to calculate the chance of recent coalescence and probability of identity by descent. We introduce an inference scheme that fits these theoretical results to the geographical covariance structure of bialleleic genetic markers. It can estimate the strength of the barrier as well as several demographic parameters. We investigate the power of our inference scheme to detect barriers by applying it to a wide range of simulated data. We also showcase an example application to aAntirrhinum majus(snapdragon) flower color hybrid zone, where we do not detect any signal of a strong genome wide barrier to gene flow.

Recently it has become feasible to detect long blocks of almost identical sequence shared between pairs of genomes. These so called IBD-blocks are direct traces of recent coalescence events, and as such contain ample signal for inferring recent demography. Here, we examine sharing of such blocks in two-dimensional populations with local migration. Using a diffusion approximation to trace genetic ancestry back in time, we derive analytical formulas for patterns of isolation by distance of long IBD-blocks, which can also incorporate recent population density changes. As a main result, we introduce an inference scheme that uses a composite likelihood approach to fit observed block sharing to these formulas. We assess our inference method on simulated block sharing data under several standard population genetics models. We first validate the diffusion approximation by showing that the theoretical results closely match simulated block sharing patterns. We then show that our inference scheme rather accurately and robustly recovers estimates of the dispersal rate and effective density, as well as bounds on recent dynamics of population density. To demonstrate an application, we use our estimation scheme to explore the fit of a diffusion model to Eastern European samples in the POPRES data set. We show that ancestry diffusing with a rate ofduring the last centuries, combined with accelerating population growth, can explain the observed exponential decay of block sharing with pairwise sample distance.