Project description:The extent to which prehistoric migrations of farmers influenced the genetic pool of western North Africans remains unclear. Archaeological evidence suggests that the Neolithization process may have happened through the adoption of innovations by local Epipaleolithic communities or by demic diffusion from the Eastern Mediterranean shores or Iberia. Here, we present an analysis of individuals' genome sequences from Early and Late Neolithic sites in Morocco and from Early Neolithic individuals from southern Iberia. We show that Early Neolithic Moroccans (∼5,000 BCE) are similar to Later Stone Age individuals from the same region and possess an endemic element retained in present-day Maghrebi populations, confirming a long-term genetic continuity in the region. This scenario is consistent with Early Neolithic traditions in North Africa deriving from Epipaleolithic communities that adopted certain agricultural techniques from neighboring populations. Among Eurasian ancient populations, Early Neolithic Moroccans are distantly related to Levantine Natufian hunter-gatherers (∼9,000 BCE) and Pre-Pottery Neolithic farmers (∼6,500 BCE). Late Neolithic (∼3,000 BCE) Moroccans, in contrast, share an Iberian component, supporting theories of trans-Gibraltar gene flow and indicating that Neolithization of North Africa involved both the movement of ideas and people. Lastly, the southern Iberian Early Neolithic samples share the same genetic composition as the Cardial Mediterranean Neolithic culture that reached Iberia ∼5,500 BCE. The cultural and genetic similarities between Iberian and North African Neolithic traditions further reinforce the model of an Iberian migration into the Maghreb.
Project description:North East Europe harbors a high diversity of cultures and languages, suggesting a complex genetic history. Archaeological, anthropological, and genetic research has revealed a series of influences from Western and Eastern Eurasia in the past. While genetic data from modern-day populations is commonly used to make inferences about their origins and past migrations, ancient DNA provides a powerful test of such hypotheses by giving a snapshot of the past genetic diversity. In order to better understand the dynamics that have shaped the gene pool of North East Europeans, we generated and analyzed 34 mitochondrial genotypes from the skeletal remains of three archaeological sites in northwest Russia. These sites were dated to the Mesolithic and the Early Metal Age (7,500 and 3,500 uncalibrated years Before Present). We applied a suite of population genetic analyses (principal component analysis, genetic distance mapping, haplotype sharing analyses) and compared past demographic models through coalescent simulations using Bayesian Serial SimCoal and Approximate Bayesian Computation. Comparisons of genetic data from ancient and modern-day populations revealed significant changes in the mitochondrial makeup of North East Europeans through time. Mesolithic foragers showed high frequencies and diversity of haplogroups U (U2e, U4, U5a), a pattern observed previously in European hunter-gatherers from Iberia to Scandinavia. In contrast, the presence of mitochondrial DNA haplogroups C, D, and Z in Early Metal Age individuals suggested discontinuity with Mesolithic hunter-gatherers and genetic influx from central/eastern Siberia. We identified remarkable genetic dissimilarities between prehistoric and modern-day North East Europeans/Saami, which suggests an important role of post-Mesolithic migrations from Western Europe and subsequent population replacement/extinctions. This work demonstrates how ancient DNA can improve our understanding of human population movements across Eurasia. It contributes to the description of the spatio-temporal distribution of mitochondrial diversity and will be of significance for future reconstructions of the history of Europeans.
Project description:The patterns of prehistoric migrations across the Bering Land Bridge are far from being completely understood: there still exists a significant gap in our knowledge of the population history of former Beringia. Here, through comprehensive survey of mitochondrial DNA genomes retained in 'relic' populations, the Maritime Chukchi, Siberian Eskimos, and Commander Aleuts, we explore genetic contribution of prehistoric Siberians/Asians to northwestern Native Americans. Overall, 201 complete mitochondrial sequences (52 new and 149 published) were selected in the reconstruction of trees encompassing mtDNA lineages that are restricted to Coastal Chukotka and Alaska, the Canadian Arctic, Greenland, and the Aleutian chain. Phylogeography of the resulting mtDNA genomes (mitogenomes) considerably extends the range and intrinsic diversity of haplogroups (eg, A2a, A2b, D2a, and D4b1a2a1) that emerged and diversified in postglacial central Beringia, defining independent origins of Neo-Eskimos versus Paleo-Eskimos, Aleuts, and Tlingit (Na-Dene). Specifically, Neo-Eskimos, ancestral to modern Inuit, not only appear to be of the High Arctic origin but also to harbor Altai/Sayan-related ancestry. The occurrence of the haplogroup D2a1b haplotypes in Chukotka (Sireniki) introduces the possibility that the traces of Paleo-Eskimos have not been fully erased by spread of the Neo-Eskimos or their descendants. Our findings are consistent with the recurrent gene flow model of multiple streams of expansions to northern North America from northeastern Eurasia in late Pleistocene-early Holocene.