XXXX pigmentation evolution: divergent genotypes underlying convergent phenotypes.

@entity1709 @entity238 @entity6014
Similar phenotypic changes have evolved independently in many animal taxa. It is unknown whether independent changes involve the same or different developmental and genetic mechanisms. Myriad pigment patterns in the genus @entity238 offer numerous opportunities to address this question. Previous studies identified regulatory and structural genes involved in the development and diversification of pigmentation in selected species. Here, we examine @entity238 americana and @entity238 novamexicana, interfertile species that have evolved dramatic pigmentation differences during the few million years since their divergence. Interspecific genetic analysis was used to investigate the contribution of five specific candidate genes and other genomic regions to phenotypic divergence by testing for associations between molecular markers and pigmentation. At least four distinct genomic regions contributed to pigmentation differences, one of which included the @entity6014 gene. @entity6014 protein was expressed at higher levels in the more yellow D. novamexicana than the heavily melanized D. americana. Because @entity6014 promotes yellow pigment formation and suppresses melanization, the expression difference and genetic association suggest that evolution at the @entity6014 locus contributed to pigmentation divergence between D. americana and D. novamexicana. Surprisingly, no genetic association with the yellow locus was detected in this study, and Yellow expression was identical in the two species. Evolution at the yellow locus underlies pigmentation divergence among other @entity238 species; thus, similar pigment patterns have evolved through regulatory changes in different genes in different lineages. These findings bear upon understanding classic models of @entity1709 and mimicry.
