AI interpretationAI-generated
Ancient DNA reveals East Tianshan was a Bronze-Iron Age melting pot of millet farmers and steppe groups.
This study sequenced 135 ancient genomes from 11 sites in the East Tianshan region of Xinjiang, dating from 3580 to 1546 years ago. It found that Bronze Age populations were formed by mixing Yellow River millet farmers with Chemurchek-related groups from the Altai, with little contribution from contemporaneous steppe pastoralists. Iron Age groups became more heterogeneous, absorbing ancestry from northern China, Mongolia, the steppe, and Central Asia. These interactions predate the Silk Road by nearly 1800 years.
- A previously unknown Bronze Age population in East Tianshan had about half Yellow River millet-farmer ancestry and half Chemurchek-related ancestry, showing that westward spread of millet farming involved population movement.
- Middle-to-Late Bronze Age steppe pastoralists contributed little ancestry to the main Bronze Age East Tianshan population, despite their widespread eastward expansion.
- Iron Age East Tianshan populations became increasingly heterogeneous through repeated, spatially uneven admixture with northern China, Mongolia, the steppe, and southern Central Asia, rather than a single migration or replacement.
Sample interpretation
The dataset includes 258 samples from 11 sites, with 200 from the Bronze Age and 58 from the Iron Age. Y-chromosome lineages are diverse, with R-M12149 (n=9), Q-F1213 (n=8), and R-M269 (n=5) among the most common. Mitochondrial DNA is dominated by F2f (n=27), D4b2b (n=18), and A6 (n=14). The largest site contributions come from Quan'ergou (97), Tianshanbeilu (56), and Ya'er (55).
For genealogy enthusiasts
For ancestry enthusiasts, this study shows that East Tianshan was a key contact zone long before the Silk Road. It highlights how ancient DNA can reveal complex, localized admixture patterns, and provides a deeper context for understanding genetic diversity in present-day Central Asian and Xinjiang populations.
Abstract
INTRODUCTION
Located between the Hexi Corridor and the Inner Asian Mountain Corridor, the East Tianshan Mountains connect northern China with the eastern steppe and Central Asia. Archaeological evidence documents the movement of millet, wheat, barley, and livestock as well as metallurgy and other technologies through this landscape during the Bronze and Iron Ages. The region therefore provides an important setting for investigating whether cultural exchange involved population movement. However, despite its strategic location, its population history has remained poorly understood because ancient genomic data have been limited.
RATIONALE
To investigate how populations formed and interacted in this contact zone, we generated genome-wide data from 135 ancient individuals from 11 archaeological sites across the East Tianshan region of Xinjiang. Spanning nearly two millennia, these individuals date from 3580 to 1546 calibrated years before present. By integrating ancient genomes with archaeological contexts and chronological evidence, we reconstructed patterns of ancestry formation, admixture, population continuity, and demographic change from the Bronze Age to the Iron Age.
RESULTS
We identified a previously unrecognized Bronze Age population distributed across several East Tianshan sites. Approximately half of its ancestry was related to Middle-to-Late Neolithic millet farming populations from the upper and middle Yellow River (YR) basin, whereas the remainder was related to Chemurchek-associated groups from the Altai and Dzungarian regions. This ancestry profile indicates that the westward spread of millet-related lifeways into the East Tianshan involved not only cultural transmission but also population movement from northern China.
A second major finding is that contemporaneous Middle-to-Late Bronze Age steppe pastoralists contributed little ancestry to the principal Bronze Age East Tianshan population, despite their widespread eastward expansion across Inner Asia. Thus, the main regional Bronze Age ancestry cannot be explained simply by the large-scale expansion of later steppe pastoralist groups. Bronze Age populations were nevertheless not genetically uniform. Some individuals showed additional connections to northern Xinjiang and northeast Asian populations. An individual from Nanwan carried predominantly Chemurchek-related ancestry together with ancestry related to the Bactria-Margiana Archaeological Complex (BMAC), a Bronze Age cultural formation centered in southern Central Asia, demonstrating that interactions also extended southward.
During the Iron Age, East Tianshan populations became increasingly heterogeneous. Many groups retained substantial ancestry from the earlier Bronze Age regional population while incorporating varying contributions related to northern China, Mongolia, the Eurasian Steppe, and southern Central Asia. Different western-derived ancestry streams appeared in different communities, indicating repeated and spatially uneven admixture rather than a single migration or wholesale population replacement.
CONCLUSION
The East Tianshan Mountains formed a long-term demographic interface linking eastern and western Eurasia. Bronze Age populations were shaped primarily by admixture between Yellow River–related millet farmers and Chemurchek-related groups, while receiving only limited ancestry from contemporaneous Middle-to-Late Bronze Age steppe pastoralists. During the Iron Age, this regional ancestry persisted alongside additional eastern, steppe-related, and Central Asian gene flow. These interactions began nearly 1800 years before the historic Silk Road, revealing deep prehistoric foundations for trans-Eurasian mobility and exchange.