A non-exhaustive survey revealed possible genetic similarity in mitochondrial adaptive evolution of marine fish species in the northwestern Pacific

Mitochondrial coding genes involved in the oxidative phosphorylation pathway play vitally important roles in energy production and thermal adaptation. Investigating the underlying molecular mechanism of mitochondrial adaptive evolution is crucial for understanding biodiversity and ecological radiation. In this study, we collated population genetic studies of marine fish species in the northwestern Pacific based on mitochondrial cytochrome b gene sequences, to investigate whether similar patterns could be detected in mitochondrial adaptive evolution. After filtering, nine studies containing eight marine fish species (Ammodytes personatus, Boleophthalmus pectinirostris, Larimichthys polyactis, Mugil cephalus, Pampus argenteus, Platycephalus sp.1, Sebastiscus marmoratus, and Trachidermus fasciatus) belonging to eight different families were retained. Multiple codon-based approaches were used to identify potential sites under selection in each species. By comparison, our results showed that the posterior part of the mitochondrial cytochrome b gene (particularly codon 372 and its neighboring sites) seemed to be involved in the adaptive evolution process, suggesting potential genetic similarity among distantly related species. We also summarized four types of adaptive patterns in the reviewed species, and suggest that the level of genetic differentiation and mitochondrial adaptive evolution might be correlated. Further studies are needed to confirm such relationship by detecting RNA-level evidence and investigating more species and samples.