DISSERTATION RESEARCH: The evolutionary origin and genetics of color pattern diversity in Phyllobates poison frogs

该项目将确定不同毒箭蛙颜色图案变化的基因。这些青蛙以其鲜艳的色彩图案而闻名，这是一种警告信号，可以阻止潜在的捕食者。在一小群毒镖蛙（叶叶蛙）中，鲜艳的亮黄色从深色条纹的祖先独立进化了多次；在一个物种中，不同的颜色变化甚至出现在同一个种群中。研究人员将利用新的基因组技术和统计分析来识别条纹蛙和纯色蛙之间的基因差异。结果将提供关键的见解遗传过程的基础上的独立进化的颜色模式变异在这组青蛙。这项研究还将揭示有益基因突变在人群内部和人群之间传播的重要信息。此外，该项目将为本科生提供研究机会。计划的外联活动包括为中小学生举办公开研讨会和教育活动。为了查明导致叶门动物物种趋同进化的遗传因素，该项目利用了颜色模式的个体发生、种间和种内变化。首先，在两对密切相关的叶门动物谱系之间，以及在哥伦比亚圣胡安河上游的一种有叶门动物（phylloates aurotaenia）种群中，颜色模式存在显著差异。研究人员将使用外显子富集和下一代测序来寻找在条纹和纯色谱系之间高度分化的位点，并在统计上与p.a aurotaenia的颜色模式变化相关。其次，使用RNAseq研究颜色发育过程中的基因表达，以确定在整个发育过程中发生颜色变化时上调或下调的基因。这两种方法将产生一组假定的基因座背后的颜色模式变化在叶状叶。然后，研究人员将结合分子系统发育学和聚结模拟来推断这些基因座的进化史，以阐明这类青蛙的亮黄色趋同进化背后的遗传机制。

This project will identify the genes responsible for color pattern variation between different Poison-dart frogs. These frogs are well known for their brightly colored patterns, which serve as warning signals to deter potential predators. Within one small group of Poison-dart frogs (Phyllobates), vivid bright yellow colorations have independently evolved multiple times from dark, striped ancestors; in one species, different color morphs even occur within the same population. The researchers will take advantage of new genomic technologies and statistical analyses to identify the genes that differ between striped and solid-colored frogs. Results will provide critical insights on the genetic processes that underlie the independent evolution of color pattern variants in this group of frogs. The research will also reveal important information on the spread of beneficial genetic mutations within and across populations. In addition, the project will provide research opportunities for undergraduate students. Planned outreach includes public seminars and educational activities for elementary and middle school children. To pinpoint the genetic elements responsible for convergent evolution across Phyllobates species, this project takes advantage of ontogenetic, interspecific, and intraspecific variation in color pattern. First there is striking variation in color pattern between two pairs of closely related Phyllobates lineages, and within a population of Phyllobates aurotaenia from the upper San Juan River in Colombia. The researchers will use exon enrichment and next-generation sequencing to find loci that are highly differentiated between striped and solid-colored lineages, and statistically associated with color pattern variation within P. aurotaenia. Second, gene expression during coloration development will be studied using RNAseq, in order to identify genes that are up or down-regulated when changes in coloration occur throughout development. These two approaches will yield a set of putative loci behind color pattern variation in Phyllobates. The researchers will then use a combination of molecular phylogenetics and coalescent simulations to infer the evolutionary history of these loci, in order to shed light on the genetic mechanisms behind the convergent evolution of bright yellow coloration in this group of frogs.