Fig. 1.

Radical amino acid changes of positively selected sites are shown above the branches across gymnotiformes species tree from a-w. Circles indicate positively selected genes across branches. Bars represent radical amino acid changes of sites detected by Datamonkey. Stars indicate amino acid substitution identified by branch-site model. Species underlined are facultative (or obligate in the case of E. electricus) air breathers. Dotted species (E. virescens) is mildly hypoxia tolerant. Hba, Hbb, Mb and Ngb are colored with green, orange, blue and pink, separately