The complete mitochondrial genome of the bubble-gum coral (Octocorallia: Coralliidae) from the seamount in the tropical Western Pacific.

The complete mitochondrial genome of Li et al. 2021, a deep-sea gorgonian inhabiting at 858 m in Caroline Ridge, was obtained in this study. The length of the mitochondrial genome is 19,018 bp with 14 protein coding genes, one transfer RNA (tRNA-Met) and two ribosomal RNA genes contained in this circular molecule. Phylogenetic analysis indicated that and Bayer, 1993 were two closely related species, and a total of 26 mutational sites (four nonsynonymous mutations included) can be detected between their mitochondrial genomes. This exhibits a case that mitochondrial genomes can be applied to differentiate closely related species in gorgonians. The phylogenetic tree constructed with mitochondrial genomes showed that the families in Octocorallia are reciprocally monophyletic, provided that the family names were revised according to the systematic revision of Octocorallia guided by phylogenomics. However, the relationships of the families within each order were different between the previous phylogenomic work and ours. Integrating mitochondrial genomes from a wider array of Octocorallia families is essential for a more accurate comparison of phylogenies derived from nuclear and mitochondrial sequences in future study.