Genetic continuity in the Franco-Cantabrian Region: new clues from autochthonous mitogenomes

Background: The Late Glacial Maximum (LGM), ∼20 thousand years ago (kya), is thought to have forced the peopleinhabiting vast areas of northern and central Europe to retreat to southern regions characterized by milder climaticconditions. Archaeological records indicate that Franco-Cantabria might have been the major source for the re-peopling ofEurope at the beginning of the Holocene (11.5 kya). However, genetic evidence is still scarce and has been the focus of anintense debate.Methods/Principal Findings:Based on a survey of more than 345,000 partial control region sequences and the analysis of53 mitochondrial DNA (mtDNA) genomes, we identified an mtDNA lineage, HV4a1a, which most likely arose in the Franco-Cantabrian area about 5.4 kya and remained confined to northern Iberia.Conclusions/Significance:The HV4a1a lineage and several of its younger branches reveal for the first time geneticcontinuity in this region and long-term episodes of isolation. This, in turn, could at least in part explain the unique linguisticand cultural features of the Basque region.This research study received support from the Fundación de Investigación Médica Mutua Madrileña (to AS), the Ministerio de Ciencia e Innovación(SAF2008-02971) (to AS), the Progetti Ricerca Interesse Nazionale 2009 (Italian Ministry of the University) (to AA and AT), the FIRB-Futuro in Ricerca (Italian Ministry of the University) (to AA and AO), the Fondazione Alma Mater Ticinensis (to AT)S