Preliminary assessment of adaptive evolution of mitochondrial protein coding genes in darters (Percidae: Etheostomatinae)

Background: Mitochondrial DNA of vertebrates contains genes for 13 proteins involved in oxidative phosphorylation. Some of these genes have been shown to undergo adaptive evolution in a variety of species. This study examines all mitochondrial protein coding genes in 11 darter species to determine if any of these genes show evidence of positive selection. Methods: : The mitogenome from four darter was sequenced and annotated. Mitogenome sequences for another seven species were obtained from GenBank. Alignments of each of the protein coding genes were subject to codon-based identification of positive selection by Selecton, MEME and FEL. Results: : Evidence of positive selection was obtained for six of the genes by at least one of the methods. CYTB was identified as having evolved under positive selection by all three methods at the same codon location. Conclusions: : Given the evidence for positive selection of mitochondrial protein coding genes in darters, a more extensive analysis of mitochondrial gene evolution in all the extant darter species is warranted.