Migration and social organization of human groups between the Neolithic and the Bronze Age in Southern France : a view from palaeogenomics

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Abstract: Through a multiscale paleogenomic approach, this study aims to document the genetic diversity of human groups in Southern France from the Neolithic to the Bronze Age in relation to the cultural transformations highlighted in the archaeological record. With a regional and diachronic perspective, this study was built around a broad chronological range, spanning from the VIth to the IInd millennium BCE, and a spatial area restricted to the Occitanie region. We focused on a corpus of eleven archaeological sites, totaling 184 analyzed human remains and providing genomic data for 78 individuals. We conducted a population-based approach, documenting regional genetic variability between the Neolithic and the Bronze Age. This allowed us to discuss the transformations in genetic pools and population dynamics identified during both the Mesolithic-Neolithic transition and the IIIrd millennium BCE. Our results reinforce the dichotomy between Continental and Mediterranean Neolithization waves. Mediterranean Neolithic diffusion appears to be associated with smaller groups, characterized by recurrent admixture with Mesolithic groups. The observation of regional genetic variability between the second phase of Neolithization and the first half of the IIIrd millennium BCE also illustrates a relative genetic continuity within the groups of southern France, despite cultural transformations. From the second half of the IIIrd millennium BCE, a different genetic ancestry originating from the Pontic steppes spreads more widely in Western Europe. Our results complement and support previous observations made at the scale of Western Europe, pointing to a later and less pronounced diffusion of this genetic ancestry in Southern France. Additionally, we characterized the genetic diversity of the studied groups at the scale of funerary sites to enhance understanding of the social functioning of these communities and their funerary practices. We extensively documented the Late Neolithic burial cavity of the Aven de la Boucle (Corconne, Gard) using genomic data, archaeo-anthropological data, and Bayesian modeling based on radiocarbon dates. The analyses revealed the existence of a patrilineal system in which the association to a specific paternal lineage and the access to the burial appear to be correlated. Through multiple scales of resolution, our results initiate the filling of a temporal and spatial gap for the groups inhabiting southern France between the VIth and Ist millennium BCE, highlighting the potential of a multidisciplinary paleogenomic approach, thus enabling a better understanding of regional funerary contexts.