Genetic structure of Sino-Tibetan populations revealed by forensic STR loci

TL;DR

This study analyzed forensic STR loci in Tibetan populations to understand their genetic structure and relationships with neighboring groups, revealing strong correlations with linguistic groups and challenging previous assumptions about Tibetan origins.

Contribution

It provides detailed genetic data on Tibetan populations using forensic STRs and clarifies their genetic relationships with other Sino-Tibetan and Asian groups, especially regarding their distinctiveness and origins.

Findings

Genetic structure correlates with linguistic affiliations.

Tibetan populations are genetically distinct from Han Chinese and Altaic groups.

Southern indigenous populations contributed to Han Chinese and Altaic gene pools.

Abstract

The origin and diversification of Sino-Tibetan populations have been a long-standing hot debate. However, the limited genetic information of Tibetan populations keeps this topic far from clear. In the present study, we genotyped 15 forensic autosomal STRs from 803 unrelated Tibetan individuals from Gansu Province (635 from Gannan and 168 from Tianzhu). We combined these data with published dataset to infer a detailed population affinities and admixture of Sino-Tibetan populations. Our results revealed that the genetic structure of Sino-Tibetan populations was strongly correlated with linguistic affiliations. Although the among-population variances are relatively small, the genetic components for Tibetan, Lolo-Burmese, and Han Chinese were quite distinctive, especially for the Deng, Nu, and Derung of Lolo-Burmese. Southern indigenous populations, such as Tai-Kadai and Hmong-Mien populations might have made substantial genetic contribution to Han Chinese and Altaic populations, but not to Tibetans. Likewise, Han Chinese but not Tibetan shared very similar genetic makeups with Altaic populations, which did not support the North Asian origin of Tibetan populations. The dataset generated here are also valuable for forensic identification.