Extensive genetic admixture between Tai-Kadai-speaking people and their neighbors from Yungui Plateau inferred from genome-wide variations

Background: Southwest China is characterized by multi-language and multi-ethnic communities and is one of the regions with the wealthiest ethnolinguistic and genetic diversity in East Asia. There are numerous Tai-Kadai (TK)-speaking populations, but the detailed evolutionary history and biological adaptations of these populations are still unclear.

Results: Here, we genotyped genome-wide SNP data of 77 unrelated TK-speaking Zhuang and Dong individuals from the Yungui Plateau and explored their detailed admixture history and adaptive features using clustering patterns, allele frequency differentiation and sharing haplotype patterns. TK-speaking Zhuangs and Dongs from Guizhou Province are closely related to geographically close Yunnan TK-speaking Dais, and geographically close Hmong-Mien (HM)-speaking populations. Besides, we identified that Guizhou TK people have a close genetic relationship with Austronesian-speaking Atayal and Paiwan people, which is supported by the common origin of the ancient Baiyue tribe. We additionally found subtle genetic differences among the newly studied Zhuang, Dong and previously reported Dai people via the fine-scale genetic substructure analysis. Finally, we identified specific selection candidate signatures associated with several essential human immune and metabolic biological functions, which can be provided evolutionary evidence for the allele frequency distribution pattern of clinical genetic risk loci.

Conclusions: our comprehensive genetic characterization of TK people suggested the strong genetic affinity within TK groups and extensive gene flow with geographically close HM people. We also provided genetic evidence that supported the common origin process of TK and Austronesian people. The fitted admixture models further suggested that ancestral sources from northern millet farmers and southern inland and coastal people contributed to the formation of the gene pool of the Zhuang and Dong people.