Under pressure: Evidence for selection on color-related genes in poison frogs of the genus Ranitomeya

posematic organisms rely on their bright conspicuous coloration to communicate to potential predators that they are toxic and unpalatable. These aposematic phenotypes are strongly tied to survival and reproduction and therefore make excellent opportunities to investigate the genetic underpinning of coloration. The family Dendrobatidae includes phenotypically diverse members of Neotropical aposematic poison frogs native to Central and South America. Significant progress has been made in elucidating the molecular mechanisms responsible for aposematic coloration in poison frogs, which have paved the way for future studies to test hypotheses of the evolution of coloration across aposematic vertebrates. However, very little is known about whether these color related genes are under positive selection. We assembled transcriptomes from publicly available data reads sets for 9 different color morphs of poison frogs in the Ranitomeya genus that display bright conspicuous coloration (four morphs of R. imitator, two morphs of R. variabilis, two morphs of R. fantastica, one morph of R. summersi) to identify protein-coding genes responsible for color development that are under positive selection.

具有警戒色（aposematic）的生物依靠其鲜亮醒目的体色，向潜在捕食者传递自身有毒且不可取食的信号。这类警戒性表型与生存和繁殖紧密关联，因此为探究体色形成的遗传基础提供了绝佳的研究契机。箭毒蛙科（Dendrobatidae）包含表型多样的新热带界警戒性毒蛙类群，原生分布于中美洲与南美洲。目前学界在阐明毒蛙警戒体色形成的分子机制方面已取得显著进展，为后续开展脊椎动物警戒体色演化相关假说的验证研究铺平了道路。然而，学界对于这些与体色相关的基因是否处于正选择压力之下仍知之甚少。本研究从公开可用的测序读段数据集中，组装了彩蛙属（Ranitomeya）9种不同体色变型的转录组——该属物种均具有鲜亮醒目的体色，具体包括模仿彩蛙（R. imitator）的4种变型、变异彩蛙（R. variabilis）的2种变型、梦幻彩蛙（R. fantastica）的2种变型以及萨默斯彩蛙（R. summersi）的1种变型，旨在鉴定参与体色发育且受正选择作用的蛋白质编码基因。