Complete mitochondrial genome of Iniistius trivittatus and unique variation in two observed inserts between rRNA and tRNA genes in wrasses

BMC Evolutionary Biology

Ming Zhang¹  Yuanyuan Zhang²  Jinquan Yang²  Wenqiao Tang³  Dong Liu³ 

[1] Department of Epidemiology and Biostatistics, University of Georgia, 30602, GA, USA;Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, 201306, Shanghai, China;Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, 201306, Shanghai, China;Key Laboratory of Exploration and Utilization Aquatic Genetic Resources, Ministry of Education, 201306, Shanghai, China;Shanghai Ocean University, National Demonstration Center for Experimental Fisheries Science Education, 201306, Shanghai, China;

关键词: Fish;    Molecular diversity;    16S rRNA;    12S rRNA;    Transposon;    Evolution;   

DOI  :  10.1186/s12862-020-01683-8

来源: Springer

【 摘 要 】

BackgroundThe family Labridae made up of 519 species in the world. The functional evolution of the feeding-related jaws leaded to differentiation of species, and the pharyngeal jaw apparatus evolved independently, but evolutionary mechanism still remain unaddressed in wrasses. Mitogenomes data can be used to infer genetic diversification and investigate evolutionary history of wrasses, whereas only eight complete mitogenomes in this family have been sequenced to date. Here, we sequenced the complete mitogenomes of Iniistius trivittatus to investigate genetic differentiation among wrasse species.ResultsWe sequenced the complete mitogenomes of I. trivittatus using a novel PCR strategy. The I. trivittatus mitogenomes is 16,820 bp in length and includes 13 protein -coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a control region. Compared to eight known mitochondrial genome, 2 additional noncoding regions (lengths of 121 and 107 bp), or so-called inserts, are found in the intergenic regions 12S rRNA - tRNAVal - 16S rRNA. The presumed origin of the two rare inserts is from tRNA- related retrotransposons. Compared with cytochrome b gene, the two insert sequences are highly conserved at the intraspecies level, but they showed significant variation and low similarity (< 70%) at the interspecies level. The insert events were only observed in I. trivittatus by checking the phylogenetic trees based on the complete mitogenomes of Labrida species. This finding provides evidence that in the mitogenomes, retrotransposon inserts result in intraspecific homoplasmy and interspecific heteroplasmy by natural selection and adaptation to various environments.ConclusionsThis study found additional mitogenome inserts limited in wrasse species. The rRNA genes with inserts might have experienced a selective pressure for adaptation to feeding modes. Such knowledge can enable a better understanding of molecular mechanism underlying morphological evolution in wrasses.

【 授权许可】

CC BY