DNA barcoding of Schizothoracinae fishes from the Yarlung Zangbo River in Tibet

The nine endemic species of the genus Schizothorax from the Yarlung Zangbo River, Tibet comprise a putative cyprinid species flock. In this study, the effectiveness of the COI DNA barcode for Schizothoracinae species identification was verified by using 45 COI sequences covering nine species in four genera of Schizothoracinae fishes. The average Kimura two parameter (K2P) genetic distances within and among species were 0.13% and 8.57%, respectively. The results revealed that most of the species were clearly discriminated by their estimated genetic distances and monophyletic clustering in a maximum likelihood tree. However, insignificant genetic distances were noticed in two reportedly valid species: Schizothorax molesworthi and S. integrilabiatus (0.1%), and the monophyly of S. macropogon could not be recovered in the schizothoracine group. The fishes of S.curilabiatus living in the lower course of Yalung Zangbo River were clustered together with three species from the upper course, which is inconsistent with the geographical distribution of the populations.