Genetic basis of aposematic coloration in a mimetic radiation of poison frogs

Abstract

AbstractThe evolution of mimicry in a single species or population has rippling inter and intraspecific effects across ecological communities, providing a fascinating mechanism of phenotypic diversification. In this study we present the first identification of genes underlying Müllerian mimicry in a vertebrate, the Peruvian mimic poison frog,Ranitomeya imitator. We sequenced 124R. imitatorexomes and discovered loci with both strong divergence between different mimetic morphs and phenotypic associations within an intraspecific admixture zone, implicatingmc1r,asip,bsn,retsat, andkrt8.2in the evolution of mimetic color phenotypes. We confirmed these associations for most candidate genes through linkage mapping in a lab-reared pedigree. We also sequenced transcriptomes from the model species, allowing tests for introgression and revealing that the mimetic resemblance betweenR. imitatorand the models evolved independently. Selection analyses of the candidate genes show that the mimicry phenotypes likely have evolved through selective sweeps acting on polygenic variation. Our results suggest that the evolutionary origins and molecular mechanisms underlying mimicry phenotypes in vertebrates may be radically different from those previously documented in invertebrates such as the iconicHeliconiusbutterfly mimicry complex.One Sentence SummaryMüllerian mimicry evolved through independent selective sweeps on color and pattern loci in the mimic poison frog.