Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
Curr Opin Genet Dev. 2021 Aug;69:82-87. doi: 10.1016/j.gde.2021.02.009. Epub 2021 Mar 17.
Phenotypic plasticity in response to environmental cues is common in butterflies, and is a major driver of butterfly wing pattern diversity. The endocrine signal ecdysone has been revealed as a major modulator of plasticity in butterflies. External cues such as day length or temperature are translated internally into variation in ecdysone titers, which in turn lead to alternate phenotypes such as seasonal wing patterns. Here we review the evidence showing that ecdysone-mediated plasticity of different wing pattern features such as wing color and eyespot size can evolve independently. Recent studies show that ecdysone regulates gene expression in Drosophila melanogaster via a chromatin remodeling mechanism. We thus propose that environmentally responsive ecdysone titers in butterflies may also function via chromatin regulation to promote different seasonal phenotypes. We present a model of ecdysone response evolution that integrates both gene regulatory architecture and organismal development, and propose a set of testable mechanistic hypotheses for how plastic response profiles of specific genes can evolve.
对环境线索的表型可塑性在蝴蝶中很常见，是蝴蝶翅膀图案多样性的主要驱动因素。蜕皮激素等内分泌信号已被揭示为蝴蝶可塑性的主要调节剂。外部线索，如日照长度或温度，在内部转化为蜕皮激素滴度的变化，进而导致季节性翅膀图案等不同表型。在这里，我们回顾了证据表明，不同翅膀图案特征（如翅膀颜色和眼斑大小）的蜕皮激素介导的可塑性可以独立进化。最近的研究表明，蜕皮激素通过染色质重塑机制调节黑腹果蝇中的基因表达。因此，我们提出蝴蝶中对环境有反应的蜕皮激素滴度也可能通过染色质调节来促进不同的季节性表型。我们提出了一个蜕皮激素反应进化的模型，该模型整合了基因调控结构和机体发育，并提出了一组可测试的机制假设，说明特定基因的可塑性反应谱如何进化。
