Modulation of bioelectric cues in the evolution of flying fishes.

Changes to allometry, or the relative proportions of organs and tissues within organisms, is a common means for adaptive character change in evolution. However, little is understood about how relative size is specified during development and shaped during evolution. Here, through a phylogenomic analysis of genome-wide variation in 35 species of flying fishes and relatives, we identify genetic signatures in both coding and regulatory regions underlying the convergent evolution of increased paired fin size and aerial gliding behaviors. To refine our analysis, we intersected convergent phylogenomic signatures with mutants with altered fin size identified in distantly related zebrafish. Through these paired approaches, we identify a surprising role for an L-type amino acid transporter, lat4a, and the potassium channel, kcnh2a, in the regulation of fin proportion. We show that interaction between these genetic loci in zebrafish closely phenocopies the observed fin proportions of flying fishes. The congruence of experimental and phylogenomic findings point to conserved, non-canonical signaling integrating bioelectric cues and amino acid transport in the establishment of relative size in development and evolution.