Genetic diversity ofOdontobutis potamophilafrom different geographic populations inferred from mtDNA control region

Odontobutis potamophila is a Chinese endemic species and an economically important fishery resource in the Yangtze River. The genetic variability of O. potamophila was studied based on the sequence analysis of mitochondrial DNA control region from 150 individuals of five geographical populations including from Dangtu (n=30), Sheyang (n=30), Yuyao (n=30), Tai Lake nearby Dongxishan (n=30) and Minjiang (n=30). Among five populations, the genetic distance between Minjiang population and other populations (0.1186-0.1223) was larger than that among four populations except for Minjiang (0.0015-0.0198). In addition, 23 haplotypes were obtained and each population had special haplotypes. The samples from five sites had high haplotype diversity (0.80510) and low nucleotide diversity (0.04028). Through Tajima's D and Fu's F neutral testing and mismatch distribution test among all geographical populations, O. potamophila did not undergo recent population expansion. During the population evolution, O. potamophila experienced a balanced selection function and maintained a stable state and population size. Moreover, the haplotype Neighbor-Joining (NJ) tree was separated two haplotype groups. The NJ tree, TCS network and median-joining network could clearly separate the haplotypes of the specimens from different areas. Analysis of molecular variance and pairwise FST revealed an obvious genetic differentiation among different geographical populations, suggesting that O. potamophila in different geographical populations should be managed and conserved separately.