Genetic structure and admixture of the Yi and Qiang in southwestern China

The Tibetan-Yi Corridor in southwestern China is well-known for the origins, migration, and evolution of Sino-Tibetan populations. Previous genetic studies have primarily focused on Han and Tibetan populations, thereby leaving the significant genetic diversity within the Tibeto-Burman groups under-researched. In this study, to explore the genetic structure and admixture history of Tibeto-Burman populations in southwestern China, we sequenced the human genomes of 100 individuals from the Qiang and Yi ethnic groups in Sichuan Province. These populations were found to have the closest genetic affinity with nearby Tibeto-Burman-speaking Tujia and Tibetan populations. The Qiang share more allele sites with northern Altaic-speaking populations, while the Yi have closer genetic relationships with southern Hmong-Mien populations. The dominant ancestry of the Yi and Qiang derived from Neolithic millet agriculturalists in the Yellow River Basin, with a smaller proportion from Neolithic coastal populations in southern China, supporting the hypothesis of a northern origin of Sino-Tibetan populations. The Yi have more southern genetic components than the Qiang, reflecting the differential genetic influences of southeastern coastal populations on these groups. In summary, this study elucidates the fine-scale genetic structure of Tibeto-Burman populations and their genetic relationships with other Chinese populations, laying the foundation for forensic genetic research in East Asian populations.