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We cloned and sequenced the complete mitochondrial DNA (mtDNA) of three tilefishes (Branchiostegus albus, Branchiostegus argentatus, and Branchiostegus japonicus) to characterize and compare their mitochondrial genomes (mitogenomes). The mitogenomes of B. albus, B. argentatus, and B. japonicus were 16,532, 16,550, and 16,541 bp long, respectively, and all consisted of 37 genes (13 protein-coding genes, 2 ribosomal RNA, and 22 transfer RNA (tRNAs)), which are typical for vertebrate mtDNA. As in other bony fishes, most genes were encoded on the H-strand, except for the nad6 and eight tRNA genes that were encoded on the L-strand. Among the 13 protein-coding genes of all three tilefishes, 2 reading-frame overlaps were found on the same strand: atp8 and atp6 overlapped by 10 nucleotides, and nad4L and nad4 overlapped by 7 nucleotides. The identity of the nad4 gene between B. albus and B. argentatus was the lowest at 87%. Conversely, the identity of the nad6 gene between B. albus and B. japonicus was the highest at 99%. Most tRNA genes were similar in length among the three species, while the tRNA-Ser((AGY)) of B. japonicus was 9 bp longer than those of B. albus and B. argentatus. The control region of the mitogenome spanned 853, 862, and 856 bp in B. albus, B. argentatus, and B. japonicus, respectively. A maximum likelihood tree constructed using 11,035 sites contained five independent groups with bootstrap values of 100% in support of their divergence. All three tilefishes examined were clustered with the Pomacanthidae species in Group II.

We determined the complete mitochondrial genomes of Pseudolabrus sieboldi and P. eoethinus, and analyzed the genome organization, codon usage, and transition/transversion mutation ratio of the mitochondrial genome. The mitochondrial genomes of P. sieboldi and P. eoethinus are 16,507 and 16,508 bp in length, respectively, and consisted of 37 genes (13 protein-coding genes, two ribosomal RNAs, and 22 transfer RNAs), which is typical for vertebrate mitochondrial DNA. All protein-coding genes of two species used the initiation codon ATG except the cytochrome c oxidase subunit (CO) 1, which began with GTG as an initiation codon. However, the termination codon for the NADH dehydrogenase subunit (ND) 6 gene encoded with TAA in P. sieboldi, and TAG in P. eoethinus. The 12S and 16S rRNA genes were 949 and 1694 bp, respectively, in P. sieboldi, and were 948 and 1693 bp in P. eoethinus. The A + T content of the two rRNA genes were 52.9% in P. sieboldi and 52.5% in P. eoethinus, which is slightly lower than that of other labrid species. The identity of the 13 protein-coding genes ranged between 67% (ND6) and 94% (CO2 and ATP8). The G + C contents of all of the protein-coding genes of P. sieboldi were slightly higher than those of P. eoethinus. Our data contribute to the identification, and further our understanding, of the comparative genetics of Pseudolabrus species distributed in East Asia.

The complete mitochondrial (mt) genome of the Chinese many-toothed snake, Sibynophis chinensis, was sequenced and found to be 17,163 bp in length. The arrangement of 13 protein-coding genes, tRNAs and rRNAs was identical to that of other common snake mt genomes. The mt protein-coding genes of S. chinensis utilized ATA, ATG, ATA and GTG as initiation codons and AGA, AGG, TAA, TAG and T as termination codons. Among three tRNA clusters (LQM, WANCY and HSL), LQM was found instead of IQM, which is common in other vertebrates. We also identified two control regions that contained several conserved elements known as conserved sequence blocks and termination-associated sequences related to mt replication and transcription.

We determined the complete nucleotide sequence of the mitochondrial (mt) genome for the longtooth grouper, Epinephelus bruneus (Perciformes, Serranidae). This mt genome, consisting of 16,686 base pairs (bp), encoded genes for 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and a noncoding control region as those found in other vertebrates, with the gene order identical to that of typical vertebrates. A major noncoding region between the trnP and trnF genes (991 bp) was considered to be the control region (D-loop). Within this sequence, 22 copies of a 17-bp tandem repeat element, 5'-TGATATTACATATATGC-3', were identified in the control region unlike previous reported Epinephelus species.