Complete mitochondrial DNA sequence of the Japanese endemic catfish Silurus lithophilus (Siluriformes: Siluridae)

Abstract

The Japanese endemic catfish Silurus lithophilus is distributed only in Lake Biwa, Lake Yogo, and their river drainages. There are four species of the genus Silurus in Japan, of which S. lithophilus has a limited distribution. This catfish needs to be collected for DNA data owing to the lack of information related to its conservation. Here, the complete mitochondrial genome of the S. lithophilus from Lake Biwa in Japan was analyzed using next-generation sequencing. The mitochondrial genome of S. lithophilus was identified as a 16,524 bp circular molecule containing 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes, along with one A + T-rich control region. The AT content was 55.89%. The heavy (H)-strand was predicted to have 12 PCGs and 15 tRNA, and 2 rRNA genes, whereas the light (L)-strand was predicted to contain one PCG and seven tRNA genes. The start codons ATG and GTG were found in 13 PCGs. The stop codons TAA, TAG, and AGA were observed in all PCGs, except CytB. All tRNA genes formed typical cloverleaf secondary structures. The molecular phylogenetic relationship, inferred using 13 PCGs (based on the maximum likelihood), was consistent with that reported in previous studies, which predicted a sister relationship between S. lithophilus and S. asotus. The results also clearly indicated that S. lithophilus is a valid species.