Mitochondrial genome sequence and gene organization of Kunar Snow trout (Schizothorax labiatus) with phylogenetic consideration

- The mitochondrial genome of S. labiatus is 61,590 base pairs with 37 genes.
- The higher A + T contents was recorded compared to G + C contents which indicates an obvious anti-guanine bias.
- The molecular phylogenetic relationship confirms the traditional phylogentics relationship of the S. labiatus.

The complete mitochondrial genome is important for determining the phylogenetic relationship of species. In the current study, we sequenced the complete mitochondrial genome of Kunar Snow trout (Schizothorax labiatus). It was found to be 61,590 bp in length having 37 genes (13 protein coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer (tRNA) genes and one putative control region (CR)). Out of the total 37 genes, 28 were encoded on heavy strand (H), whereas 9 on light strand (L). A + T content of nucleotide were 58.04% and G + C were 41.94%. ATG was a start codon for all the proteins except COXI which has GTG as a start codon. The stop codons were TAG and TAA or incomplete stop codons (TA- and T--). The l6S rRNA genes was located between the tRNA-Val and tRNA-Leu (UUR) genes, whereas the 12S rRNA located between the tRNA-Phe and tRNA-Val. 22 tRNA genes were interspersed along the genome, in the typical structure for S. labiatus. These tRNA genes had ranged in size from 66 to 85 nucleotides, which were predicted to fold into the expected cloverleaf secondary structures with normal base pairing. The control region was located between the tRNA-Pro and tRNA-Phe genes with 936 bp. Several conserved sequence blocks (CSB) were also identified within D-loop sequences. The phylogenetic analysis based on complete mitochondrial genome sequence, showed that S. labiatus has close genetic relationships with 20 species (mostly cyprinids) and its mitogenome sequence would be useful to know the phylogenetic status of the S. labiatus.