Genomic ancestry and social dynamics of the last hunter-gatherers of Atlantic France.

Since the early Holocene, western and central Europe was inhabited by a genetically distinct group of Western Hunter-Gatherers (WHGs). This group was eventually replaced and assimilated by the incoming Neolithic farmers. The western Atlantic façade was home to some of the last Mesolithic sites of mainland Europe, represented by the iconic open-air sites at Hoedic and Téviec in southern Brittany, France. These sites are known for the unusually well-preserved and rich burials. Genomic studies of Mesolithic European hunter-gatherers have been limited to single or a few individuals per site and our understanding of the social dynamics of the last Mesolithic hunter-gatherers of Europe and their interactions with incoming farmers is limited. We sequenced and analyzed the complete genomes of 10 individuals from the Late Mesolithic sites of Hoedic, Téviec, and Champigny, in France, four of which sequenced to between 23- and 8-times genome coverage. The analysis of genomic, chronological and dietary data revealed that the Late Mesolithic populations in Brittany maintained distinct social units within a network of exchanging mates. This resulted in low intra-group biological relatedness that prevented consanguineous mating, despite the small population size of the Late Mesolithic groups. We found no genetic ancestry from Neolithic farmers in the analyzed hunter-gatherers, even though some of them may have coexisted with the first farming groups in neighboring regions. Hence, contrary to previous conclusions based on stable isotope data from the same sites, the Late Mesolithic forager community was limited in mate-exchange to neighboring hunter-gatherer groups, to the exclusion of Neolithic farmers.

READv2: advanced and user-friendly detection of biological relatedness in archaeogenomics.

The advent of genome-wide ancient DNA analysis has revolutionized our understanding of prehistoric societies. However, studying biological relatedness in these groups requires tailored approaches due to the challenges of analyzing ancient DNA. READv2, an optimized Python3 implementation of the most widely used tool for this purpose, addresses these challenges while surpassing its predecessor in speed and accuracy. For sufficient amounts of data, it can classify up to third-degree relatedness and differentiate between the two types of first-degree relatedness, full siblings and parent-offspring. READv2 enables user-friendly, efficient, and nuanced analysis of biological relatedness, facilitating a deeper understanding of past social structures.