Characterization of the Complete Mitochondrial Genomes of the Barcheek Trevally, Carangoides plagiotaenia, and the Doubled-lined Mackerel, Grammatorcynus bilineatus, from Beqa Lagoon in Fiji

Abstract

The complete mitochondrial genomes of two species from Beqa lagoon in Fiji. Carangoides plagiotaenia and Grammatorcynus bilineatus were determined by the combination of next generation sequencing (NGS) and conventional PCR methods. The size of complete mitochondrial genomes was 16,551 bp for C. plagiotaenia and 16,537 bp for G. bilineatus respectively. Each mitogenome was made up of 37 typical set of eukaryotic genes which consisted of 13 protein coding genes, 2 ribosomal RNAs (12S rRNA and 16S rRNA), 22 tRNA genes. Besides two non-coding regions, the origin of light strand replication (OL) and D-loop as a putative control region were also well conserved in both mitogenomes. The circular mitogenomes of both species accommodated 28 genes on their heavy strands (H) and nine genes on their light strands (L), for which ND6 protein coding genes were harboured on the L-strands. The A+T and G+C nucleotide percentage contents were 54.9% and 45.1% for barcheek trevally, whereas 53.21% and 46.79% for doubled-lined mackerel. The phylogenetic tree uncovered that Carangoides plagiotaenia and Carangoides bajad formed a monophyletic group with 90.58% nucleotide sequence identity, and Grammatorcynus bilineatus never formed a distinctive clade with other reported fish in the family Scombridae. The genetic information for both fish will contribute to data collections of complete mitochondrial sequences for marine finfish which will be valuable for developing conservation strategies for the species.