Complete mitochondrial genome sequence of Pseudocaranx dentex and phylogenetic analysis of Carangidae

Pseudocaranx dentex belongs to Actinopterygii, Perciformes, Carangidae, Caranginae, Pseudocaranx, and it is widely distributed in the warm waters of Indo-Pacific and Atlantic Ocean. It is mainly distributed in the South China Sea and East China Sea. The research on the breeding of P. dentex in China is still in the initial stage, and there are few reports about the genetic background of this species. As a species with high nutritional and economic values, it was studied from the perspective of molecular biology. The complete mitochondrial genome of P. dentex was obtained by second-generation sequencing and analyzed through the related software. The results showed that the mitochondrial genome was a typical circular DNA structure, with the total length of the sequence 16 570 bp, and the base composition was A (27.2%), G (17.18%), C (30.24%) and T (25.38%). It contained 13 protein-coding genes, 22 tRNA genes and 2 rRNA genes. Except for ND6, tRNA^Gln, tRNA^Ala, tRNA^Asn, tRNA^Cys, tRNA^Tyr, tRNA^Ser, tRNA^Glu, tRNA^Pro, all the other genes were encoded on the H-strand. Except for ATC and ATA, the starting codon of CO Ⅰ and ND5 were ATG; the A + T contents of mitochondrial genome and protein encoding genes were 52.58% and 51.55% respectively, and the noncoding control region (D-loop) is rich in 61.69%, which had an obvious A+T bias. Among the 22 tRNA genes, except for tRNA^ser-GCT, the other 21 tRNA genes contained typical secondary structure of clover. The phylogenetic tree was constructed with the complete sequence of mitochondrial genome of 18 species belonging to 13 genera of Carangidae fishes. Each species has an independent branch, and P. dentex and Carangoides equula belong to the same branch in the evolutionary tree, which indicated that these two species are closely related to each other. Our findings could help to explore the genetic relationship between P. dentex and other Carangidae fish, and provide a basis for germplasm identification, phylogenetic evolution analysis, genetic diversity evaluation and utilization of P. dentex.