Genetic structures of the Tibetans and the Deng people in the Himalayas viewed from autosomal STRs

Abstract

In the previous studies, the populations in Tibet exhibited a complicated genetic structure, indicating that those populations might be the admixture of East Asian and South/Central Asian populations, or have a North Asian origin. However, there have not been sufficient genetic data to support this hypothesis. In this study, we analyzed 15 autosomal polymorphic tetranucleotide short tandem repeat loci (D5S818, FGA, D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51) for three populations from Tibet, namely, Deng/Mishmi (n=114), Qamdo Tibetan (n=78) and Lhasa Tibetan (n=101). The total number of observed alleles and the average heterozygosity for all samples were 394 and 0.7574, respectively. Analysis of molecular variance and estimated G(ST) (0.0198) for these allele frequency data suggested the genetic divergence among Tibetan populations was significant. Furthermore, our new allele frequency data for 13 loci were compared with those of 41 world populations previously reported. Results from phylogenetic and multidimensional scaling analyses indicated that: (1) the Deng in Tibet has unique genetic characteristics different from the Tibetans; (2) populations living in the Himalayas area (Deng, Luoba/Adi) composed of a distinct cluster and are closely related to each other than to any other ethnic groups in East Asia; (3) the Tibetans are most similar to the North Asians. This genetic structure is consistent with the geographical barriers and linguistic classifications.