Genetic polymorphisms and phylogenetic analyses of the Ü-Tsang Tibetan from Lhasa based on 30 slowly and moderately mutated Y-STR loci

As a result of the expansion of old Tibet on the Qinghai-Tibet Plateau,Tibetans diverged into three main branches,Ü-Tsang,Amdo,and Kham Tibetan.Ü-Tsang Tibetans are geographically distributed across the wide central and western portions of the Qinghai-Tibet Plateau while Lhasa is the central gathering place for Tibetan culture.The AGCU Y30,a 6-dye fluorescence kit including 30 slowly and moderately mutated Y-STR loci,has been validated for its stability and sensitivity in different biomaterials and diverse Chinese populations(Han and other minorities),and widely used in the practical work of forensic science.However,the 30 Y-STR profiling of Tibetan,especially forÜ-Tsang Tibetan,were insufficient.We utilized the AGCU Y30 to genotype 577Ü-Tsang Tibetan unrelated males from Lhasa in the Tibet Autonomous Region of China to fill up the full and accurate Y-STR profiles.A total of 552 haplotypes were observed,536(97.10%)of which were unique.One hundred and ninety-four alleles were observed at 26 single copy loci and the allelic frequencies ranged from 0.0017 to 0.8180.For the two multi-copy loci DYS385a/b and DYS527a/b,64 and 36 allelic combinations were observed,respectively.The gene diversity(GD)values ranged from 0.3079 at DYS391 to 0.9142 at DYS385a/b and the overall haplotype diversity(HD)was 0.9998,and its discrimination capacity(DC)was 0.9567.The population genetic analyses demonstrated that LhasaÜ-Tsang Tibetan had close relationships with other Tibetan populations from Tibet and Qinghai,especially withÜ-Tsang Tibetan.From the perspective of Y haplogroups,the admixture of the southward Qiang people with dominant haplogroup O-M122 and the northward migrations of the initial settlers of East Asia with haplogroup D-M175 hinted the Sino-Tibetan homologous,thus,we could not ignore the gene flows with other Sino-Tibetan populations,especially for Han Chinese,to characterize the forensic genetic landscape of Tibetan.