Genome-wide patterns of selection in 230 ancient Eurasians

Ancient DNA makes it possible to observe natural selection directly by analysing samples from populations before, during and after adaptation events. Here we report a genome-wide scan for selection using ancient DNA, capitalizing on the largest ancient DNA data set yet assembled: 230 West Eurasians who lived between 6500 and 300 bc, including 163 with newly reported data. The new samples include, to our knowledge, the first genome-wide ancient DNA from Anatolian Neolithic farmers, whose genetic material we obtained by extracting from petrous bones, and who we show were members of the population that was the source of Europe’s first farmers. We also report a transect of the steppe region in Samara between 5600 and 300 bc , which allows us to identify admixture into the steppe from at least two external sources. We detect selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height. The first genome-wide scan for selection using ancient DNA, based on data from 230 West Eurasians dating between to 6500 and 300 bc and including new data from 163 individuals among which are 26 Neolithic Anatolians, provides a direct view of selection on loci associated with diet, pigmentation and immunity. Selection pressures deduced from ancient DNA This study uses ancient DNA as a window on a crucial period of human evolution — the arrival of farming in Europe around 8,500 years ago. Genome-wide scanning data was obtained from 230 West Eurasians from between 6500 BC and 300 BC, including samples from 26 Anatolian Neolithic individuals, representing the first genome-wide ancient DNA from the eastern Mediterranean. The authors find evidence of selection on loci associated with diet, pigmentation and immunity. The strongest signal of selection is at the allele responsible for lactase persistence, supporting the view that an appreciable frequency of lactase persistence in Europe only dates to the past four thousand years.