Admixture-introduced complex landscape of genetic diversity contributed to the extensive Southwestern Chinese ethnolinguistic diversity

Abstract

Fine-scale genetic background characterization of ethnolinguistically diverse populations can gain new insights into the population admixture processes, which is essential for evolutionary and medical genomic research. However, the genetic diversity and population history of southern Chinese indigenous people and their interaction with historic incomers keep unknown. Here, we genotyped 700K genome-wide SNPs from four Guizhou populations belonging to Tai-Kadai (TK), Hmong-Mien (HM), and Tibeto-Burman language families and merged them with publicly available data from 218 modern and ancient East Asian groups to perform one comprehensive demographical and evolutionary history reconstruction. We found that Guizhou populations harbored a strong genetic substructure correlated with language categories. We comprehensively characterized the genetic signatures of geographically diverse HM people and identified the unique HM genetic lineage in Southwest China and Southeast Asia as their shared ancestry component in the demographical history reconstruction. Our identified admixture signatures and times further supported the hypothesis that the HM people originated from Yungui Plateau and then southward migration during the historical period. Admixture models focused on SinoTibetan and TK people supported their intense interaction and harbored the most extensive gene flows consistent with their shared linguistic and cultural characteristics and lifestyles. Estimates of identity-bydescent sharing and effective population size showed the extensive population stratification and gene flow events in different time scales. This work focuses on the genetic features of high-density SNP markers, presents one complete landscape of the evolutionary history of ethnolinguistically different southern Chinese populations, and fills the gap of missing diversity in South China.