Comparative mitochondrial genome analysis of Neodontobutis hainanensis and Perccottus glenii reveals conserved genome organization and phylogeny.

• We reported the first complete mitochondrial genome sequence of N. hainanensis. • Highly conserved genome organization and phylogeny between N. hainanensis and P. glenii. • The divergence of Neodontobutis and Perccotus was later than that of Odontobutis. • Stronger selective constraints in PCGs for P. glenii compared with other Odontobitidae. To investigate the molecular evolution of mitochondrial genomes among the family Odontobutidae, the complete mitochondrial genomes of Neodontobutis hainanensis and Perccottus glenii were sequenced and compared with seven odontobutids species. The genome organization, base composition, codon usage, and gene arrangement of N. hainanensis exhibited high similarity to P. glenii compared to those of other Odontobutidae species. Reconstructed phylogenetic analyses of Odontobutidae strongly supported that Neodontobutis and Perccottus formed a unifying group sister to Odontobutis. Our molecular dating time revealed that the two species diverged approximately 21.7 Ma during Miocene, later than that of Odontobutis. Selection analyses showed stronger selective constraints in mitochondrial genes for P. glenii. However, two positively selected sites in NADH4 and NADH6 genes were respectively detected in N. hainanensis and P. glenii , indicating that they might evolve different metabolic performance in response to the contrasting environments. [ABSTRACT FROM AUTHOR]