Comparative Mitogenomics of the Genus Sebastes (Scorpaenidae, Scorpaeniformes) Revealed Conserved Gene Rearrangement and High Sequence Variations

Abstract

To understand the molecular evolution of mitochondrial genomes in the genus Sebastes, the mitogenome of Sebastes taczanowskii was sequenced and compared with those of another ten Sebastes species. The complete mitogenome of S. taczanowskii was a circular molecule of 16,452 bp containing 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes and a control region. The positive AT skew (0.023) indicated the occurrence of more As than Ts. The arrangement of 13 PCGs was similar to that of other sequenced rockfishes. All PCGs were initiated by ATG codons, except for the cytochrome c oxidase subunit 1 (cox1) gene, which was initiated by the GTG sequence, as observed in other rockfishes. Our results displayed similar mitogenome features among species in genome organization, base composition, codon usage, and gene rearrangement. The identical gene rearrangement of trnH-trnS-trnL tRNA cluster observed in mitogenomes of these fourteen closely related rockfishes suggests that this unique gene order is conserved within Sebastes. These mitogenomes exhibit a high level of sequence variation, mainly due to the differences of corresponding intergenic sequences in gene rearrangement regions and the heterogeneity of tandem repeats in the control regions.ii was a circular molecule of 16,452 bp containing 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes and a control region. The positive AT skew (0.023) indicated the occurrence of more As than Ts. The arrangement of 13 PCGs was similar to that of other sequenced rockfishes. All PCGs were initiated by ATG codons, except for the cytochrome c oxidase subunit 1 (cox1) gene, which was initiated by the GTG sequence, as observed in other rockfishes. Our results displayed similar mitogenome features among species in genome organization, base composition, codon usage, and gene rearrangement. The identical gene rearrangement of trnH-trnS-trnL tRNA cluster observed in mitogenomes of these fourteen closely related rockfishes suggests that this unique gene order is conserved within Sebastes. These mitogenomes exhibit a high level of sequence variation, mainly due to the differences of corresponding intergenic sequences in gene rearrangement regions and the heterogeneity of tandem repeats in the control regions.