Genetic Structure and Genetic Differentiation of Tibetan Mastiff Populations

[ Objective] To analyze the genetic structure and genetic differentiation of Tibetan Mastiff populations and provide a theoretical basis for the protection and rational development and utilization of the Tibetan Mastiff breed resources. [ Method] A total of 86 blood samples were collected from two populations of Hequ Tibetan Mastiff （HTM） and Qinghai Tibetan Mastiff （QTM）. The genetic structure and genetic differentiation of nine blood protein loci of ＂If, Po, Es-1, Es-2, S（alpha）2, Hb, AIb, Pr and Amy between these two populations were examined by vertical polyacrylam- ide gel electrophoresis with discontinuous buffer system. [ Result] The effective number of alleles （Ne）, Shannon genetic diversity index （I） and Nei average expected gene heterozygosity （H） of the HTM were respectively 1.690 7, 0.485 5 and 0.295 9, and these were higher than those of QTM. The Nei＇s standard genetic distance （D） between HTM and QTM was 0.012 3, and the degree of genetic similarity was 0.987 8. The gene flow （Nm） of these two Tibetan Mastiff populations was 14.543 7. [ Conclusion] The genetic variability of intra-population of HTM was higher than that of QTM, and the genetic differentiation of inter-population was very low （ GsT = 0.018 7）. Thereby, the great gene flow （ Nm = 14.543 7） is the main factor leading to the low genetic differentiation of the inter-population in different geographical groups.