Phenotypic plasticity is the ability of a single genotype to produce different phenotypes in response to environmental variation. The importance of phenotypic plasticity in natural populations and its contribution to phenotypic evolution during rapid environmental change is widely debated. Here, we show that thermal plasticity of gene expression in natural populations is a key component of its adaptation: evolution to novel thermal environments increases ancestral plasticity rather than mean genetic expression. We determined the evolution of plasticity in gene expression by conducting laboratory natural selection on a Drosophila simulans population in hot and cold environments. After more than 60 generations in the hot environment, 325 genes evolved a change in plasticity relative to the natural ancestral population. Plasticity increased in 75% of these genes, which were strongly enriched for several well-defined functional categories (e.g., chitin metabolism, glycolysis, and oxidative phosphorylation). Furthermore, we show that plasticity in gene expression of populations exposed to different temperatures is rather similar across species. We conclude that most of the ancestral plasticity can evolve further in more extreme environments.

中文翻译：

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表型可塑性响应温度胁迫的演变

表型可塑性是单个基因型响应环境变化而产生不同表型的能力。表型可塑性在自然群体中的重要性及其在快速环境变化期间对表型进化的贡献受到广泛争论。在这里，我们表明自然群体中基因表达的热可塑性是其适应的关键组成部分：向新的热环境的进化增加了祖先的可塑性，而不是平均基因表达。我们通过在炎热和寒冷环境中对模拟果蝇种群进行实验室自然选择，确定了基因表达可塑性的进化。在炎热的环境中经历了60多代之后，325个基因相对于自然祖先种群进化出了可塑性的变化。这些基因中 75% 的可塑性增加，这些基因的几个明确的功能类别（例如几丁质代谢、糖酵解和氧化磷酸化）得到了强烈富集。此外，我们发现暴露于不同温度的种群基因表达的可塑性在不同物种之间非常相似。我们的结论是，大多数祖先的可塑性可以在更极端的环境中进一步进化。