First report of complete mitochondrial genome of Schizothorax curvifrons using next generation sequencing platform (NGS) and phylogentic relationship with other Schizothoracinae

The structure and gene organisation of fish mitochondrial genomes are often conservative due to extensive global study on the genome for evolutionary and other genetic reasons. This study used the Illumina platform to sequence the mitochondrial (mt) genome of snow trout (Schizothorax curvifrons). The S. curvifrons mt genome is approximately 16,592 kb and contains 37 genes (13 protein-coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and one putative control region (CR). 28 genes are encoded on the heavy strand (H), and 9 on the light strand (L). The nucleotide composition is 55.06% A + T and 44.94% G + C. The start codon for most proteins is ATG, except for COXI, which uses GTG. The 16S rRNA gene is situated between the tRNA-Val and tRNA-Leu genes, while the 12S rRNA gene is between the tRNA-Phe and tRNA-Val genes. The 22 tRNA genes range from 65 to 85 nucleotides in length. The control region spans 938 bp and is located between the tRNA-Pro and tRNA-Phe genes. Phylogenetic analysis revealed that S. curvifrons clusters with S. niger, whereas S. esocinus and S. labiatus form a distinct lineage. This study provides the complete mitochondrial genome of S. curvifrons, aiding in resolving ambiguities among Schizothorax species and guiding future research and conservation strategies.