When populations evolve adaptive reaction norms in response to novel environments, it can occur through a process termed genetic accommodation. Under this model, the initial response to the environment is widely variable between genotypes as a result of cryptic genetic variation, which is then refined by selection to a single adaptive response. Here, I empirically test these predictions from genetic accommodation by measuring reaction norms in individual genotypes and across several time points. I compare two species of Drosophila that differ in their adaptation to ethanol (D. melanogaster and D. simulans). Both species are human commensals with a recent cosmopolitan expansion, but only D. melanogaster is adapted to ethanol exposure. Using gene expression as a phenotype and an approach that combines information about expression and alternative splicing, I find that D. simulans exhibits cryptic genetic variation in the response to ethanol, while D. melanogaster has almost no genotype-specific variation in reaction norm. This is evidence for adaptation to ethanol through genetic accommodation, suggesting that the evolution of phenotypic plasticity could be an important contributor to the ability to exploit novel resources.

中文翻译：

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具有不同生态历史的姊妹物种（果蝇（Drosophila melanogaster）和D. simulans）之间对乙醇响应的可塑性演变。

当人群响应新环境而发展适应性反应规范时，它可以通过称为遗传适应的过程发生。在此模型下，由于隐秘的遗传变异，基因型之间对环境的初始响应差异很大，然后通过选择将其优化为单个适应性响应。在这里，我通过测量单个基因型和多个时间点的反应规范，从遗传适应性角度经验性地检验了这些预测。我比较了果蝇对乙醇的适应能力不同的两种果蝇（D. melanogaster和D. simulans）。这两个物种都是人类的纪念物，最近有世界性的扩张，但只有黑腹果蝇适用于乙醇暴露。使用基因表达作为表型以及结合表达和选择性剪接的信息的方法，我发现D. simulans在对乙醇的反应中表现出隐秘的遗传变异，而D. melanogaster在反应规范中几乎没有基因型特异性变异。这是通过遗传适应适应乙醇的证据，表明表型可塑性的演变可能是开发新资源的能力的重要贡献者。