title: Molecular evidence for the subspecific differentiation of blue sheep (Pseudois nayaur) and polyphyletic origin of dwarf blue sheep (Pseudois schaeferi).
abstract: Blue sheep (Pseudois nayaur), a Central Asian ungulate with restricted geographic distribution, exhibits unclear variation in morphology and phylogeographic structure. The composition of species and subspecies in the genus Pseudois is controversial, particularly with respect to the taxonomic designation of geographically restricted populations. Here, 26 specimens including 5 dwarf blue sheep (Pseudois schaeferi), which were collected from a broad geographic region in China, were analyzed for 2 mitochondrial DNA fragments (cytochrome b and control region sequences). In a pattern consistent with geographically defined subspecies, we found three deeply divergent mitochondrial lineages restricted to different geographic regions. The currently designated two subspecies of blue sheep, Pseudois nayaur nayaur and Pseudois nayaur szechuanensis, were recognized in the phylogenetic trees. In addition, the Helan Mountain population showed distinct genetic characteristics from other geographic populations, and thus should be classified as a new subspecies. In contrast, dwarf blue sheep clustered closely with some blue sheep from Sichuan Province in the phylogenetic trees. Therefore, dwarf blue sheep appear to be a subset of Pseudois nayaur szechuanensis. After considering both population genetic information and molecular clock analysis, we obtained some relevant molecular phylogeographic information concerning the historical biogeography of blue sheep. These results also indicate that western Sichuan was a potential refugium for blue sheep during the Quaternary period.
authors: Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, People's Republic of China.
authors: Shuai
authors: S
authors: Tan
authors: Dandan
authors: D
authors: Zou
authors: Lei
authors: L
authors: Tang
authors: Gaochao
authors: G
authors: Wang
authors: Quekun
authors: Q
authors: Peng
authors: Bo
authors: B
authors: Zeng
authors: Chen
authors: C
authors: Zhang
authors: Fangdong
authors: F
authors: Zou
mesh_terms: D000818:Animals; D002681:China; D004272:DNA, Mitochondrial / Q000235:genetics*; D019143:Evolution, Molecular; D005828:Genetics, Population; D005843:Geography; D009154:Mutation; D059645:Mutation Rate; D010802:Phylogeny; D012756:Sheep / Q000145:classification / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial