Polymorphism Of D-loop Sequence From MtDNA Of Onychostoma Rara

Onychostoma rara is a wild fish species, with high economic value, in Barbinae, Cyprinidae and Cypriniformes. It is distributed only in the Yuanjiang River and the Xijiang River systems. Onychostoma rara has been recorded as the endangered sepces in "China Species Red List" now. The genetic diversity of this species has not been studied so far.The study on mitochondrial DNA (mtDNA) is a hot field in molecular biology research recently. With some special characteristics, mitochondrial DNA as an ideal genetic marker has been successfully applied to the research of population and evolutionary biology of fishes. In this paper, the genetic diversity of Onychostoma rar was studied for the first time by method of mtDNA sequencing.A total of 25 variable sites, including 23 transitions and 2 transitions with transversion, were detected in mtDNA of the endangered species Onychostoma rara after determination of the 478bp sequences from 3' end of mtDNA D-loop in the 30 specimen of the species collected from the Qingshui River in Guizhou. The 30 specimen belong to 18 haplotypes according to the determined sequences. The nucleotide diversity (71) of the 30 specimen was 0.0107, and the Average number of nucleotide diffences (K) of them was 5.092. The haplotypic diversity (H) was 0.940, and the genetic distances (P) between the haplotypes of the species averaged0.014. The NJ and UPGMA phylogenetic tree of the 18 haplotypescomprised 2 branches. The populations of Onychostoma rara includehigh mtDNA diversity.