Complete mitochondrial genome and phylogenetic analysis of Sinogastromyzon szechuanensis (Teleostei, Cypriniformes, Homalopteridae)

Sinogastromyzon szechuanensis is endemic to the Upper Yangtze River in China. In this study, we first determined the complete mitochondrial genome of S. szechuanensis. The circular mitogenome was 16,565 bp in length, including 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and 2 main noncoding regions. Most mitochondrial genes were encoded on the H-strand, except for ND6 and eight tRNA genes. The overall nucleotides composition was 30.38% A, 25.26% T, 27.74% C, and 16.62% G, with AT bias of 55.64%, respectively. Phylogenetic analysis using concatenated nucleotide sequences of the 13 PCGs with two different methods (ML and NJ) both highly supported that S. szechuanensis showed a close relationship with S. puliensis and S. sichangensis. These data would be useful for further studies on genetic diversity and molecular phylogenetic relationship of the family Homalopteridae.