Investigating the genetic basis of aposematic coloration in poison frogs
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Date
2023-11-29
Access
2025-12-01
Authors
Rubio, Andrew Otto
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Publisher
East Carolina University
Abstract
Aposematic organisms rely on their conspicuous appearance to signal that they are defended and unpalatable. Such phenotypes are strongly tied to survival and reproduction. Aposematic colors and patterns are highly variable; however, the genetic, biochemical and physiological mechanisms producing this conspicuous coloration have not yet been elucidated. Here, I attempt to 1) identify genes and gene networks potentially affecting color variation in two color morphs of Ranitomeya imitator: the orange-banded Sauce and the red-headed Varadero morphs, 2) identify the overall effects of dietary carotenoids on pigmentation and gene expression on R. imitator frogs, and 4) identity genes associated with color development that are under positive selection in poison frogs (Amphibia: Anura: Dendrobatidae). My results show that key genes may be playing vital roles in producing bright aposematic coloration. In addition, we found that genes related to lipid storage were up-regulated in the tissue of Ranitomeya imitator froglets that were fed a carotenoid enriched diet. Lastly, we found key genes related to color formation to be under positive selection when testing transcriptome data from a set of poison frog species in the family Dendrobatidae. These three chapters will allow us to make some preliminary inferences concerning the relevance of our results to important general issues in ecology and evolution. For instance, results from this dissertation could help identify expression levels of a wide variety of different genes that are involved in determining differences in color pattern between different mimetic morphs of R. imitator, and between this mimic and its model species. In addition, results from this dissertation can pave the way for future studies to test hypotheses of mechanisms of color morph maintenance in populations and investigate the evolution of color pattern across aposematic vertebrates in a phylogenetic context.