The mitochondrial lineage U8a reveals a Paleolithic settlement in the Basque

Background It is customary, in population genetics studies, to consider Basques as the direct descendants of the Paleolithic Europeans. However, until now there is not an irrefutable genetic proof to support this supposition. Even studies based on mitochondrial DNA (mtDNA), an ideal molecule to construct datable maternal genealogies, have failed in this attempt. It could be possible that incoming gene flow has replaced the Basque ancient lineages but it could be also possible that these lineages have not been detected due to a lack of resolution of the Basque mtDNA genealogies. To deal with this possibility we analyzed here the mtDNA of a large sample of autochthonous Basques using mtDNA genomic sequencing for those lineages that could not be unequivocally classified by diagnostic RFLP analysis and control region (HVSI and HVSII) sequencing. Results We show that Basques have the most ancestral phylogeny in Europe for the rare mitochondrial subhaplogroup U8a. Divergence times situate the Basque origin of this lineage in the Upper Palaeolithic. Most probable, their primitive founders came from West Asia. The lack of U8a lineages in Africa points to an European and not a North African route of entrance. Phylogeographic analysis suggest that U8a had two expansion periods in Europe, the first, from a south-western area including the Iberian peninsula and Mediterranean France before 30,000 years ago, and the second, from Central Europe around 15,000-10,000 years ago.