Fine‐scale genetic structure of Tujia and central Han Chinese revealing massive genetic admixture under language borrowing

Archaeological, genetic, and linguistic evidence has supported the idea that northern China is the original center of modern Sino-Tibetan-speaking populations. However, the demographic history of subsequent southward migration and genetic admixture of Han Chinese with surrounding indigenous populations remain uncharacterized, and the language shifts and assimilations accompanied by movement of people, or just an adaptation of cultural ideas among populations in central China is still unclear, especially for Tibeto-Burman-speaking Tujia and central Han Chinese populations. To resolve this, we genotyped over 60K genome-wide markers in 505 unrelated individuals from 63 indigenous populations. Our results showed both studied Han and Tujia were at the intermediate position in the modern East Asian North-South genetic cline and there was a correlation between the genetic composition and the latitude. We observed the strong genetic assimilation between Tujia people and central Han Chinese, which suggested massive population movements and genetic admixture under language borrowing. Tujia and central Han Chinese could be modeled as a two-way admixture deriving primary ancestry from a northern ancestral population closely related to the ancient DevilsCave and present-day Tibetans and a southern ancestral population closely related to the present-day Tai-Kadai and Austronesian-speaking groups. The ancestral northern population we suspect to be related to the Neolithic millet farming groups in the Yellow River Basin or central China. We showed that the newly genotyped populations in Hubei Province had a higher proportion of DevilsCave or modern Tungusic/Mongolic-related northern ancestries, while the Hunan populations harbored a higher proportion of Austronesian/Tai-Kadai-related southern ancestries.