This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A multidisciplinary study has answered key questions about how agricultural practices diffused into ancient Gansu from Eurasia, as well as described population movements and burial practices in the Gansu region thousands of years ago. 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.
In addition to its genetic focus, the study also included information on Late Neolithic and Bronze Age social and burial practices, based on an investigation of the large cemetery at Mogou (3,600–3,200 years before the present)—one of the largest excavated cemeteries in China. The researchers noted that genetic similarities among the Gansu sites revealed a broad correlation—though not a strict alignment—between genetic ancestry and archaeologically defined cultural groups. Through kinship and identity-by-descent (IBD) analyses, most Mogou individuals were found to form a broadly linked network based on biological relatedness that persisted through the transition from the Qijia to the Siwa archaeological cultures, pointing to a continuous and connected society.
The researchers also found evidence of endogamy at Mogou, as two individuals showed signs of parental consanguineous mating, while runs of homozygosity segments suggested that Mogou may also have practiced some level of exogamy, with some mates coming from outside communities. Furthermore, female and male individuals at Mogou did not exhibit significant differences in relatedness, suggesting that the Mogou community did not strictly maintain either patrilocal or matrilocal residence patterns. By integrating burial practices and genetic patterns, the results showed that genetic outliers—individuals who were not close biological relatives of core community members—were more likely to be buried in settings archaeologically interpreted as lower status.
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