Person:

Lazaridis, Iosif

The Yamnaya archaeological complex appeared around 3300 BCE across the steppes north of the Black and Caspian Seas, and by 3000 BCE reached its maximal extent from Hungary in the west to Kazakhstan in the east. To localize Yamnaya origins among preceding Eneolithic people, we assembled ancient DNA from 428 individuals, demonstrating three genetic clines. A “Caucasus-Lower Volga” (CLV) Cline suffused with Caucasus hunter-gatherer1 ancestry extended between a Caucasus Neolithic southern end, and a northern end at Berezhnovka along the Lower Volga river. Bidirectional gene flow created intermediate populations, such as north Caucasus Maikop people, and those at Remontnoye on the steppe. The “Volga Cline” was formed as CLV people mixed with upriver populations of Eastern hunter-gatherer2 ancestry, creating hyper-variable groups as at Khvalynsk. The “Dnipro Cline” was formed as CLV people moved west, mixing with Ukraine Neolithic hunter-gatherers3 along the Dnipro river to establish Serednii Stih groups from whom Yamnaya ancestors formed around 4000 BCE and grew explosively after 3750-3350 BCE. CLV people contributed four-fifths of the ancestry of the Yamnaya, and, entering Anatolia likely from the east, at least a tenth of the ancestry of Bronze Age Central Anatolians, where Hittite was spoken4,5. We thus propose that the final unity of the speakers of “Proto-Indo-Anatolian”, the language ancestral to both Anatolian and Indo-European, was among CLV people sometime between 4400-4000 BCE.

The north Black Sea (Pontic) Region was the nexus of the farmers of Old Europe and the foragers and pastoralists of the Eurasian steppe1,2, and the source of waves of migrants that expanded deep into Europe3–5. We report genome-wide data from 78 prehistoric North Pontic individuals to understand the genetic makeup of the people involved in these migrations and discover the reasons for their success. First, we show that native North Pontic foragers had ancestry not only from Balkan and Eastern hunter-gatherers6but also from European farmers and, occasionally, Caucasus hunter-gatherers. More dramatic inflows ensued during the Eneolithic, when migrants from the Caucasus-Lower Volga area7moved westward, bypassing the local foragers to mix with Trypillian farmers advancing eastward. People of the Usatove archaeological group in the Northwest Pontic were formed ca. 4500 BCE with an equal measure of ancestry from the two expanding groups. A different Caucasus-Lower Volga group, moving westward in a distinct but temporally overlapping wave, avoided the farmers altogether, and blended with the foragers instead to form the people of the Serednii Stih archaeological complex7. A third wave of expansion occurred when Yamna descendants of the Serednii Stih forming ca. 4000 BCE expanded during the Early Bronze Age (3300 BCE). The temporal gap between Serednii Stih and the Yamna expansion is bridged by a genetically Yamna individual from Mykhailivka in Ukraine (3635-3383 BCE), a site of uninterrupted archaeological continuity across the Eneolithic-Bronze Age transition, and the likely epicenter of Yamna formation. Each of these three waves propagated distinctive ancestries while also incorporating outsiders during its advance, a flexible strategy forged in the North Pontic region that may explain its peoples' outsized success in spreading their genes and culture across Eurasia3–5,8–10.

Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000-875 BCE, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across Central and Western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2-6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain’s independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in Central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in Central Europe over this period.