title: Ethnically distinct populations of historical Tibet exhibit distinct autosomal STR compositions.
abstract: At an average altitude of 4000m above sea level, the Tibetan plateau is one of the highest plains on the planet. It is surrounded on three sides by massive mountain ranges: the Kunlun, the Karakoram and the Himalayas. These natural barriers have kept Tibet relatively isolated. In the present study, 15 autosomal STR loci were genotyped in 338 unrelated individuals from three traditional provinces of historical Tibet: Amdo (86), Kham (101) and U-Tsang (151). All the studied loci were in Hardy-Weinberg equilibrium except for the D19S433 locus in the Kham province. FGA, D21S11 and D2S1338 show the highest observed heterozygosity values in Amdo (0.8954), Kham (0.9208) and U-Tsang (0.8940), respectively, whereas TPOX is the least variable marker displaying the lowest value for the same parameter. U-Tsang exhibits the highest total numbers of alleles (139) followed by Kham (130) and Amdo (128) groups. The allele frequency data from this study were compared to relevant global reference populations. Our results indicate that although these three Tibetan populations group together in both the Correspondence Analysis (CA) plot and the Neighbor Joining (NJ) tree, they exhibit some degree of genetic differentiation among themselves congruent with their unique dialects, cultures and traditions. The 15 autosomal STR loci studied were found to be informative and discriminating, thereby providing a useful set of markers for population genetic studies.
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India.
authors.forename: Thupten
authors.initials: T
authors.lastname: Tsering
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Canada.
authors.forename: Tenzin
authors.initials: T
authors.lastname: Gayden
authors.affiliation: Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Chennakrishnaiah
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India.
authors.forename: Areej
authors.initials: A
authors.lastname: Bukhari
authors.affiliation: Department of Molecular Biology, Colorado College, Colorado Springs, CO, USA. Electronic address: rbertrand@coloradocollege.edu.
authors.forename: Ralph
authors.initials: R
authors.lastname: Garcia-Bertrand
authors.affiliation: Department of Molecular Biology, Colorado College, Colorado Springs, CO, USA.
authors.forename: Rene J
authors.initials: RJ
authors.lastname: Herrera
mesh_terms: D044466:Asian People / Q000208:ethnology* / Q000235:genetics*; D005787:Gene Frequency; D014644:Genetic Variation; D006579:Heterozygote; D006801:Humans; D018895:Microsatellite Repeats; D010802:Phylogeny; D044382:Population Groups / Q000235:genetics; D018609:Tibet / Q000208:ethnology
keywords: Amdo; Autosomal STR; Kham; Phylogenetics; Plateau; Tibet; U-Tsang