A common goal in evolutionary biology is to discern the mechanisms that produce the astounding diversity of morphologies seen across the tree of life. Aposematic species, those with a conspicuous phenotype coupled with some form of defence, are excellent models to understand the link between vivid colour pattern variations, the natural selection shaping it, and the underlying genetic mechanisms underpinning this variation. Mimicry systems in which multiple species share the same conspicuous phenotype can provide an even better model for understanding the mechanisms of colour production in aposematic species, especially if comimics have divergent evolutionary histories. Here we investigate the genetic mechanisms by which vivid colour and pattern are produced in a Müllerian mimicry complex of poison frogs. We did this by first assembling a high-quality de novo genome assembly for the mimic poison frog Ranitomeya imitator. This assembled genome is 6.8 Gbp in size, with a contig N50 of 300 Kbp R. imitator and two colour morphs from both Ranitomeya fantastica and R. variabilis which R. imitator mimics. We identified a large number of pigmentation and patterning genes that are differentially expressed throughout development, many of them related to melanocyte development, melanin synthesis, iridophore development and guanine synthesis. Polytypic differences within species may be the result of differences in expression and/or timing of expression, whereas convergence for colour pattern between species does not appear to be due to the same changes in gene expression. In addition, we identify the pteridine synthesis pathway (including genes such as qdpr and xdh) as a key driver of the variation in colour between morphs of these species. Finally, we hypothesize that genes in the keratin family are important for producing different structural colours within these frogs.

中文翻译：

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拟态基因组学：整个发育过程中的基因表达提供了对苗勒拟态系统中趋同和发散表型的见解


进化生物学的一个共同目标是辨别生命树中产生令人震惊的形态多样性的机制。防御物种，即具有显着表型并具有某种防御形式的物种，是了解鲜艳的颜色图案变异、塑造它的自然选择以及支撑这种变异的潜在遗传机制之间联系的绝佳模型。多个物种共享相同显着表型的拟态系统可以为理解警戒物种的颜色产生机制提供一个更好的模型，特别是当拟态动物具有不同的进化历史时。在这里，我们研究了毒蛙苗勒拟态复合体产生鲜艳颜色和图案的遗传机制。为此，我们首先为模仿毒蛙Ranitomeya 模仿者组装了高质量的从头基因组。该组装基因组大小为 6.8 Gbp，重叠群 N50 为 300 Kbp R。模仿者和来自Ranitomeya Fantasya和R 的两种颜色变形。变量其中R .模仿者模仿。我们鉴定出大量在整个发育过程中差异表达的色素沉着和图案基因，其中许多与黑素细胞发育、黑色素合成、虹彩细胞发育和鸟嘌呤合成相关。物种内的多型差异可能是表达和/或表达时间的差异的结果，而物种之间颜色模式的趋同似乎并不是由于基因表达的相同变化所致。 此外，我们确定蝶啶合成途径（包括qdpr和xdh等基因）是这些物种之间颜色变化的关键驱动因素。最后，我们假设角蛋白家族中的基因对于在这些青蛙中产生不同的结构颜色很重要。