The complete mitochondrial genome sequence of Plotosus japonicus (Siluriformes: Plotosidae) and phylogenetic studies of Siluriformes

In this study, we first determined and described the complete mitogenome sequence of Plotosus japonicus, which is a kind of marine fish widely distributed in Northwest Pacific. The complete mitogenome sequence is 16 472 bp in length, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, a putative control region (CR) and a light-strand replication origin (OL). The overall base composition is 31.9% A, 24.7% T, 27.7% C, 15.7% G, with a slight AT bias (56.6%), similar to other vertebrate mitochondrial genomes. All the protein-coding genes use the initiation codon ATG except COI uses GTG. Most of them have TAA or TAG as the stop codon, while COII and ND4 use AGA, COIII and Cytb use an incomplete stop codon TA or T. Maximum Likelihood (ML) tree and Bayesian analyses based on concatenated nucleotide sequences of 12 mitochondrial protein-coding genes were constructed and both yielded identical topologies. These results are expected to provide useful molecular data for species identification and further phylogenetic studies of Siluriformes.