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