ゲノミクス：古代ヨーロッパ人の移動経路を明らかにする

The detailed movements of ancient Europeans are revealed in analyses of genomic data published in Nature and Nature Ecology & Evolution this week. The findings shed light on the genomic history and changing fortunes of populations from the Upper Palaeolithic through to the Neolithic.

Modern humans arrived in Europe around 45,000 years ago. They lived as hunter-gatherers through challenging times, including the Last Glacial Maximum (25,000 to 19,000 years ago). Archaeologists know about the distinct cultures that emerged during this time from the artefacts left behind, but a paucity of human fossils means that little is known about the movements and interactions of the people themselves.

In the Nature paper, Cosimo Posth and colleagues analysed the genomes of 356 ancient hunter-gatherers, including new genomic data from 116 individuals from 14 countries in western and central Eurasia, dating from 35,000 to 5,000 years ago. They identify a previously unknown ancestry, in individuals from western Europe associated with the Gravettian culture, that survived during the Last Glacial Maximum in individuals from southwestern Europe and spread northeastward with the expansion of the Magdalenian culture after this period. By contrast, southern Europe saw a local population replacement over the Last Glacial Maximum as ancestries associated with the Epigravettian culture entered the Italian peninsula, likely from the Balkans. An ancestry closely related to these Epigravettian-associated individuals then spread across Europe from around 14,000 years ago, largely replacing the Magdalenian-associated gene pool.

The study helps to resolve a long-standing archaeological debate on the origins and spread of the Magdalenian culture at the end of the Last Glacial Maximum. It also suggests that some archaeological cultures may have emerged in response to intermixing, and others were more likely to have been linked to environmental change, with or without associated genetic turnovers.

An independent paper published in Nature Ecology & Evolution reports genome-wide data from 16 further individuals from southern Spain, including a 23,000-year-old male individual from Cueva del Malalmuerzo associated with the Solutrean industry. Vanessa Villalba-Mouco and colleagues found that this Malalmuerzo individual carried genetic ancestry that links earlier Aurignacian-associated ancestry with Magdalenian-associated ancestry from after the Last Glacial Maximum. This scenario of genetic continuity in southern Spain contrasts with the genetic discontinuity either side of the Last Glacial Maximum reported by Posth and colleagues in Italy, suggesting different population dynamics for southern European refugia as humans lived through the extremes of the last Ice Age.