Wing shape and environmental energy are associated with molecular evolutionary rates in a large avian radiation

Abstract

Among the macroevolutionary drivers of molecular evolutionary rates, metabolic demands and environmental energy have been a central topic of discussion. The large number of studies examining these associations have found mixed results, and have rarely explored the interactions among various factors impacting molecular evolutionary rates. Taking the diverse avian family Furnariidae as a case study, we examined the association between several estimates of molecular evolutionary rates with a proxy of metabolic demands imposed by flight (wing morphology) and proxies of environmental energy across the geographic ranges of species (temperature and UV radiation). We found a strong positive association between molecular rates in genomic regions that can change the coded amino-acid with wing morphology, environmental temperature, and UV radiation. Strikingly, however, we did not find evidence of such associations with molecular rates at sites not impacting amino-acids. Our results suggest that the demands of flight and environmental energy primarily impact genome evolution by placing selective constraints, instead of being associated with basal mutation rates.