Molecular Phylogeography Of The Chinese Takin(Budorcus Taxicolor)

The takin (Budorcas taxicolor) is a typical Asian species. It mainly distributes in southwest mountain region of China and there are also several populations locating in Burma, India, Nepal and Bhutan. Four subspecies of takin, Golden Takin (B. t. bedfordi), Sichuan Takin (B. t. tibetana), Mishmi Takin (B. t. Taxicolor) and Bhutan Takin (B. t. whitei) have been accepted, based on morphological differences and geographic separation. Takin is currently threatened by habitat loss, fragmentation and human persecution. In order to devise adequate conservation and management strategies for this endangered species, it is important to incorporate a reliable understanding of its population structure and evolutionary history, the existence of demorgraphic partitions throughout its geographical range, and a characterization of the distribution of genetic diversity. We have investigated the molecular phylogeography of takin, including the distribution of genetic diversity, population structure and demographic history of takin across their geographical range by analyzing 330 base pairs of the mitochondrial DNA(mIDNA ) D-loop region in 40 individuals sampled from the Qinling Mountains in Shaanxi Province, Bailongjiang in Gansu Province, Minshan Mountains, Qionglai Mountains in Sichuan Province and Gongshan Mountains in Yunnan Province. 330bp region located both in the central conserved domain and in right domain of the mtDNA D-loop revealed only 4 different haplotypes and 10 variable sites among 40 takin individuals studied. There are no transversions and insertion/deletions sites. The average divergence within 4 haplotypes is 1.66%. The result indicates that the genetic diversity within population was exactly low, supporting the possibility of recent historical population bottleneck and high level gene flow. Another most striking result is that these haplotypes exhibit a precise phylogeographie pattern, without common widespread haplotypes existing within populations. According to the distribution of haplotypes and subspecies, takin sampled could be devided into 3 completely isolated geographic units: Qinling geographic units~ Sichuan geographic units and Yunan geographic units. From the two phylogenetic trees based on Neighbor-Joining and maximum parsimony methods respectively. populations located in Gannan are suggested to be classified as Goldern Takin (B. t. -2- bedford) rather than Sichuan Takin (B. t. bedford). Analysis using (1) ~ (based on frequencies and genetic distances between haplotypes ) yielded statistically significant subdivision (bootstrap values p