The genetic history of the Southern Arc: A bridge between West Asia and Europe | Science

Abstract

INTRODUCTION For thousands of years, humans moved across the “Southern Arc,” the area bridging Europe through Anatolia with West Asia. We report ancient DNA data from 727 individuals of this region over the past 11,000 years, which we co-analyzed with the published archaeogenetic record to understand the origins of its people. We focused on the Chalcolithic and Bronze Ages about 7000 to 3000 years ago, when Indo-European language speakers first appeared. RATIONALE Genetic data are relevant for understanding linguistic evolution because they can identify movement-driven opportunities for language spread. We investigated how the changing ancestral landscape of the Southern Arc, as reflected in DNA, corresponds to the structure inferred by linguistics, which links Anatolian (e.g., Hittite and Luwian) and Indo-European (e.g., Greek, Armenian, Latin, and Sanskrit) languages as twin daughters of a Proto-Indo-Anatolian language. RESULTS Steppe pastoralists of the Yamnaya culture initiated a chain of migrations linking Europe in the west to China and India in the East. Some people across the Balkans (about 5000 to 4500 years ago) traced almost all their genes to this expansion. Steppe migrants soon admixed with locals, creating a tapestry of diverse ancestry from which speakers of the Greek, Paleo-Balkan, and Albanian languages arose. The Yamnaya expansion also crossed the Caucasus, and by about 4000 years ago, Armenia had become an enclave of low but pervasive steppe ancestry in West Asia, where the patrilineal descendants of Yamnaya men, virtually extinct on the steppe, persisted. The Armenian language was born there, related to Indo-European languages of Europe such as Greek by their shared Yamnaya heritage. Neolithic Anatolians (in modern Turkey) were descended from both local hunter-gatherers and Eastern populations of the Caucasus, Mesopotamia, and the Levant. By about 6500 years ago and thereafter, Anatolians became more genetically homogeneous, a process driven by the flow of Eastern ancestry across the peninsula. Earlier forms of Anatolian and non–Indo-European languages such as Hattic and Hurrian were likely spoken by migrants and locals participating in this great mixture. Anatolia is remarkable for its lack of steppe ancestry down to the Bronze Age. The ancestry of the Yamnaya was, by contrast, only partly local; half of it was West Asian, from both the Caucasus and the more southern Anatolian-Levantine continuum. Migration into the steppe started by about 7000 years ago, making the later expansion of the Yamnaya into the Caucasus a return to the homeland of about half their ancestors. CONCLUSION All ancient Indo-European speakers can be traced back to the Yamnaya culture, whose southward expansions into the Southern Arc left a trace in the DNA of the Bronze Age people of the region. However, the link connecting the Proto-Indo-European–speaking Yamnaya with the speakers of Anatolian languages was in the highlands of West Asia, the ancestral region shared by both.