Complete mitochondrial genome of the hybrid grouper Hyporthodus septemfasciatus (♀) × Epinephelus lanceolatus (♂).

The complete mitochondrial genome of the novel hybrid grouper (Hyporthodus septemfasciatus ♀ × Epinephelus lanceolatus ♂) includes 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNA genes, and 1 control region (D-loop) for a total length of 16,559 bp. The overall nucleotide composition encoded on the heavy strand comprises 28.64% A, 28.26% C, 16.26% G, and 26.84% T.

In this study, we report the complete mitogenome of the novel hybrid grouper Hyporthodus septemfasciatus (♀) × Epinephelus lanceolatus (♂) in Tongyeong, Republic of Korea (34°49′36.8″N, 128°20′01.6″E). Fry of the hybrid were sampled immediately after hatching and preserved in 99% ethyl alcohol in September 2019. The extracted hybrid grouper DNA specimen is stored at Soonchunhyang University in Republic of Korea (voucher no. SUC-19260). The complete mitochondrial genome (GenBank accession no. MT709278) includes 13 protein-coding genes, 2 ribosomal RNAs (rRNA), 22 transfer RNA (tRNA) genes, and 1 control region (D-Loop), for a total length of 16,559 bp. The encoded genes are similar to those of other Serranidae species (Kim et al. 2016; Tang et al. 2016; Wang et al. 2016). Most genes are encoded on the heavy strand, except for NADH dehydrogenase subunit 6 (ND6). Eight tRNA genes (tRNA-Gln, Ala, Asn, Cys, Tyr, Ser, Glu, and Pro) are encoded on the light strand. The total length of the 13 protein-coding genes (PCGs) is 11,469 bp. Among these, 12 PCGs start with ATG; the one remaining PCG is COX1 (starting with GTG). We identified three types of stop codons: TAA, with nine PCGs (ATP6, ATP8, COX1, COX3, ND1, ND2, ND4L, ND5, and ND6); AGA, with three PCGs (COX2, CYTB and ND4); and TAG, with one PCG (ND3). The overall nucleotide composition encoded on the heavy strand was 28.64% A, 28.26% C, 16.26% G, and 26.84% T. G + C content (44.53%) is less than that of A + T (55.48). The length of the mitochondrion DNA is 16,559 bp, which is 184 bp shorter than that of E. lanceolatus (Wang et al. 2014). Composition analysis revealed differentiation from E. lanceolatus in nucleotide frequencies, as 2.09% A, 0.50% C, 2.83% G, and 1.28% T. The 22 tRNA genes vary in length from 67 to 76 bp. The 12S rRNA, with a length of 956 bp, is located between tRNA-Phe and tRNA-Val, and the 16S rRNA, with a length of 1,709 bp, is located between tRNA-Val and tRNA-Leu. The control region (D-loop), with a length of 851 bp, is located between tRNA-Pro and tRNA-Phe. A molecular phylogenetic tree was constructed using the neighbor joining method based on complete mitochondrion genes among five species of Epinephelus, two species of Cephalophlis, and two species of Hyporthodus (Figure 1).

Figure 1.

Molecular phylogenetic tree of complete mitochondrion genes among 5 species of Epinephelus, 2 species of Cephalopholis, and 2 species of Hyporthodus. The phylogenetic tree was constructed using neighbor joining.