Ancient DNA suggests western farming reached Gansu without mass migration

Research Article (open access)

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Gansu, now a province in northwestern China, has long been a key crossroads for transcontinental exchanges of domesticated crops and livestock. Yet it has not been clear whether such exchanges were driven by human migration—a process known as demic diffusion—or by the introduction of crops and livestock to existing populations—a process known as cultural diffusion.

Now, researchers using genomic data from 149 ancient individuals in Gansu have shown that the introduction of western-derived agriculture amid waves of trans-Eurasian exchange was not accompanied by direct demic diffusion.

The study, published in Cell on Sept. 3, was conducted by a research team led by Fu Qiaomei from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences (CAS), working in collaboration with multiple institutions.

The genomic data used in the study date from around 4,700–3,000 years ago—a critical period when cereals and livestock first domesticated in western Eurasia were introduced to the region.

According to the researchers, the results did not detect any traces of genetic influence from western Eurasia or Central Asia among the ancient individuals, despite the adoption of western-derived crops or livestock at nine of the 11 Gansu sites.

Instead, the dominant genetic ancestries detected in Gansu were linked to populations that once inhabited the Yellow River basin, the southeastern Mongolian Plateau and the Tibetan Plateau. A few genetic outliers also pointed to interactions between Gansu and regions both nearby and farther north, including the Cis-Baikal area.

These results suggest that the introduction of western-derived domesticates did not involve a direct large-scale western population influx—unlike patterns of agricultural expansion found in Europe and Central Asia. Possible explanations for this phenomenon chiefly include cultural diffusion through the Inner Asian Mountain Corridor or transmission via exchange networks or intermediary populations across the Mongolian Steppe.