Archaeogenomics of the Gauls: From geographic and cultural structuration to genomic diversity

The Iron Age period occupies an important place in French history, as the Gauls are regularly presented as the direct ancestors of the extant French population. We documented here the genomic diversity of communities originating from six distinct French regions throughout the Iron Age. The 49 newly acquired genomes permitted us to highlight clear genetic continuity between Bronze Age and Iron Age groups in France, lending support to a cultural transition linked to progressive local economic changes rather than to a massive influx of allochthone groups. Genomic analyses revealed strong genetic homogeneity among the regional groups associated with distinct archaeological cultures. This genomic homogenisation appears to be linked to individuals' mobility between regions as well as gene flow with neighbouring groups from England and Spain. Thus, the results globally support a common genomic legacy for the population referred to as 'Celts' by the Greeks and Romans that could be linked to recurrent gene flow between culturally differentiated communities.