Genetic diversity and taxonomic status of Gymnocypris chilianensis based on the mitochondrial DNA D-loop region

To analyse the genetic diversity and taxonomic status of <i>Gymnocypris chilianensis</i>, <i>D-loop</i> region of the mitochondrial DNA was sequenced in 50 individuals of <i>G. chilianensis</i> obtained from two geographic locations (Heihe River and Shule River) and 25 individuals of <i>G. przewalskii</i>. These samples were analyzed for genetic diversity and sequence divergence, and 25 homologous sequences of another affinity <i>G. eckloni</i> downloaded from GenBank were analyzed. The results revealed that <i>G. chilianensis</i> of the Shule River showed lower haplotype diversity (Hd = 0.963) as well as nucleotide diversity (Pi = 0.00414) than the other populations, indicating that <i>G. chilianensis</i> of the Shule River should be protected preferentially due to its lower level of genetic diversity. The study also demonstrated the genetic distance of <i>G. chilianensis</i> in both Heihe River and Shule River was 0.0013, and the genetic distances between the aforementioned two populations and the <i>G. przewalskii</i> were 0.0143 and 0.0137, respectively. The genetic distances between the two <i>G. chilianensis</i> populations and the <i>G. eckloni</i> were 0.0148 and 0.0141, respectively. The NJ phylogenetic trees showed that <i>G. chilianensis</i> had further genetic distance with <i>G. eckloni</i> and <i>G. przewalskii</i>. Therefore, <i>G. chilianensis</i> could be considered as an independent species of <i>Gymnocypris</i>.