DNA barcodes and their characteristic diagnostic sites analysis of Schizothoracinae fishes in Qinghai province.

The Qinghai-Tibetan Plateau (QTP), the source and upper reaches of many Asian rivers, are crisscrossed by rivers and dotted with lakes. Schizothoracinae fishes, species native to the QTP, are distributed widely through these rivers and lakes. Over the past decades, ecological protection has become increasingly intense. The rapid acquisition of the genetic information and accurate gene sequence database are assumed to play an important role in the conservation of species diversity and biodiversity. In this study, 153 sequences (648bp in length) covering 13 species in 8 genera of Schizothoracinae fishes in Qinghai Province were used to determine whether barcode could identify Schizothoracinae species accurately. The average Kimura two parameter (K2P) genetic distances within and among species were 0.35% and 8.83%, respectively. The maximum K2P distance within species was observed in (1.36%) while minimum K2P distance among species was observed between and (0.23%). Overlaps existed in K2P distance intra- and inter- species based on both the genes. Eleven groups with 9 single-species groups and 2 multi-species groups were identified through Automatic Barcode Gap Discovery System, which were consistent with the overlaps of K2P distance. 96.7% as the accurate ratio for barcode was calculated and high solution was observed in the phylogenetic trees based on gene and gene. Except for the similar results based on two genes above, barcode was more economical than gene. The SOM model successfully predicted characteristic-diagnostic sites at species level: 36 characteristic-diagnostic sites from eight species, in which 12 from , 2 from , 7 from , 2 from , 2 from , 3 from , 3 from and 5 from . Our results show that Schizothoracinae fishes can be identified validly by using DNA barcode. Thirty-six characteristic-diagnostic sites were proposed to be applied into works of species identification for the Schizothoracinae fishes in Qinghai Province.