The complete mitochondrial genome sequence of Triplophysa bleekeri (Teleostei, Balitoridae, Nemacheilinae).

The genus Triplophysa (plateau loach) is a highly diverse group in the family Balitoridae with 133 valid species, and they play an important role in zoogeographic study of the Qinghai-Tibet Plateau. In this study, we sequenced the complete mitochondrial genome of a Triplophysa species, Triplophysa bleekeri. Combined with the complete mitogenome sequences of other 10 balitorids, the phylogenetic position of T. bleekeri was estimated. The mitochondrial genome of T. bleekeri is similar to those of the typical vertebrates, 16,568 bp in length, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding control region (D-loop). In the D-loop region, two pair of motifs, "TACAT" and its reverted and complemented sequence "ATGTA", can be found in the domain of termination-associated sequence; six conserved sequences (CSB-F, CSB-E, CSB-D, and CSB I-III) can be identified by searching some conserved motifs. Phylogenetic analyses showed that the three Triplophysa species clustered together, with T. bleekeri sister to Triplophysa stoliczkai. The two genera Triplophysa and Barbatula formed a sister-group relationship, the genus Lefua located in the intermediate position, and the genus Schistura was in the basal position in the subfamily Nemacheilinae. Further investigations with more Triplophysa species included need to be performed to better understand the evolutionary history of this intriguing genus.