The genomic history of the Iberian peninsula over the past 8000 years.

Abstract

The lberian Península provides an excellent context in which to assess the final impact of population movements entering the European continent from the east as well as prehistoric and historie connections with North Africa. We report new genome-wide data from 271 ancient individuals from Iberia, providing the most comprehensive genetic time transect of any world region over the last 8,000 years. We document population structure in the peninsula's hunter-gatherers, with northwestern but not southeastern individuals showing increased genetic affinity to central European hunter-gatherers in the centuries befare the arrival of farmers. We provide evidence of sporadic contacts from North Africa beginning at least -4,500 years ago, and by -4,000 years ago the replacement of -40% of the autosomal ancestry and 100% of the Y-chromosomes of Bronze Age groups by migrants ultimately originating in the steppe. From the lron Age, we report genome-wide data from individuals excavated in non-lndo-European speaking regions and show that they were genetically similar to contemporaries from an lndo-European-speaking region in harboring substantial proportions of steppe ancestry. With the exception of Basques who remain broadly similar to lron Age populations, during the past 2,500 years lberian populations were affected by additional gene-flow from the central/eastern Mediterranean region, probably associated with the Roman conques!, and from North Africa during the period of Muslim rule but also in earlier periods.