Tracing bronze to iron age population dynamics in Northwest Xinjiang using ancient time-series genomic data

BACKGROUND: Northwestern Xinjiang is situated at the confluence of the central Eurasian Steppe, the Inner Asian Mountain Corridor and the Tianshan mountains, and is home to rich archaeological, cultural and genetic diversity. However, the local population dynamics remain poorly understood due to the lack of time-series ancient DNA data. RESULTS: We analyze DNA from ten individuals from the Narensu site in northwestern Xinjiang spanning the Chalcolithic to the Iron Age. Our findings reveal that the earliest inhabitants of northwestern Xinjiang were formed by a genetic admixture of Ancient North Eurasians and Altai hunter-gatherers around 6000 years ago. The simultaneous arrival of ancestry related to the Bactria Margiana Archaeological Complex from Central Asia and Afanasievo-related populations from the Steppe in the early Bronze Age was detected, thereby highlighting the important role of the Inner Asian Mountain Corridor as a migration route between southern Central Asia and Xinjiang. This may also have involved the formation of the Chemurchek population in Altai, northern Xinjiang bordering Russia. Eurasian steppe ancestry identified in Narensu has changed to the late Bronze Age Sintashta populations, and eastern Eurasian ancestry from Baikal turns prominent since the Iron Age. CONCLUSIONS: Here, by reconstructing the population dynamics from the Chalcolithic to the Iron Age, our study reveals that the Narensu inhabitants have continuously accumulated with multiple waves of gene influx from surrounding regions. Altogether, these findings provide a comprehensive picture into the population fusion history of northwestern Xinjiang as well as across the Eurasian continent.