Characterization of the Whole Mitogenome of Largehead Hairtail Trichiurus lepturus (Trichiuridae): Insights into Special Characteristics.

Mitochondrial genomes are valuable for making inferences regarding population genetics, phylogenetics and recently in understanding adaptive variation in OXPHOS genes. Ribbon fish, Trichiurus lepturus is distributed in the Indian Ocean and contributes to a major share of pelagic fish landings. Considering the importance, we characterized the complete mitogenome of large head hairtail T. lepturus from Indian waters by PCR amplification and sequencing. The entire mitogenome is 16,840 bp in length, with 13 protein coding genes, 2 subunit ribosomal RNA genes, and 1 control region similar to other vertebrates. Genome contains only 21 tRNAs (tRNAPro is absent) as against 22 tRNAs reported in other vertebrates. The putative origin of L-strand replication (OL) was located in a cluster of five tRNA genes (WANCY region) and may not be functional due to the variation of conserved motif (5'-GCCGG-3') and loop. These two unusual features are common for Trichiurus mitogenomes. Phylogenetic analysis supported the monophyly of Trichiuridae. This study will provide information for further studies on taxonomy, phylogeny and patterns of adaptive evolution in the mitogenome of Trichiurus species.