[A genetic sub-structure study of the Tibetan population in Southwest China]

Tibetan is a typical ethnic minority population in Southwest China, which can be divided into U-Tsang, Kham, Amdo, Jiarong and other sub-populations. However, the genetic structure of these sub-populations has not been comprehensively analyzed, especially from the perspective of paternal and maternal lineages. Based on genetic markers of autosomes, the Y chromosome and mitochondria, we studied four Tibetan populations (the U-Tsang population in Tibet Autonomous Region; the Kham population in Garze, Sichuan province; the Amdo population in Qinghai province and the Jiarong population in Aba, Sichuan province) to interpret their genetic structure. The mini-sequencing technology was used to detect the genotype of each maker. Meanwhile, the PowerPlex ^?Y23 and DNA Typer ^TM Y26 kit were applied to genotype Y-STRs. Subsequently, the genetic structure was analyzed by heatmap and principal component analysis, ancestry component, haplogroup frequency, network map and multi-dimensional scaling analysis. The results showed that the four Tibetan populations could be divided into three sets based on the autosomal and Y-chromosomal genetic markers, in which set 1 was the U-Tsang population in the Tibetan Plateau, set 2 comprised of the Kham and Amdo populations in the surrounding areas of the plateau, and set 3 was the Jiarong population that resided in the Tibetan and Yi Corridor. No significant difference was observed in mitochondrial genetic markers among four Tibetan populations. In general, multi-category genetic information provides a new comprehensive insight into the Tibetan sub-population.