Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
Evolution. 2012 Jun;66(6):1976-84. doi: 10.1111/j.1558-5646.2011.01566.x. Epub 2012 Feb 3.
Theory predicts that developmental plasticity, the capacity to change phenotypic trajectory during development, should evolve when the environment varies sufficiently among generations, owing to temporal (e.g., seasonal) variation or to migration among environments. We characterized the levels of cellular plasticity during development in populations of Drosophila melanogaster experimentally evolved for over three years in either constant or temporally variable thermal environments. We used two measures of the lipid composition of cell membranes as indices of physiological plasticity (a.k.a. acclimation): (1) change in the ratio of phosphatidylethanolamine (PE) to phosphatidylcholine (PC) and (2) change in lipid saturation (number of double bonds) in cool (16°C) relative to warm (25°C) developmental conditions. Flies evolved under variable environments had a greater capacity to acclimate the PE/PC ratio compared to flies evolved in constant environments, supporting the prediction that environments with high among-generation variance favor greater developmental plasticity. Our results are consistent with the selective advantage of a more environmentally sensitive allele that may have associated costs in constant environments.
理论预测，当环境在代际之间发生足够大的变化时，即由于时间（例如季节性）变化或在环境之间迁移，发育可塑性（即在发育过程中改变表型轨迹的能力）应该会进化。我们在经过三年以上的实验进化后，在恒定或随时间变化的热环境中，对黑腹果蝇种群在发育过程中的细胞可塑性水平进行了描述。我们使用细胞膜脂质组成的两个指标来衡量生理可塑性（也称为适应）：（1）磷脂酰乙醇胺（PE）与磷脂酰胆碱（PC）的比例变化，以及（2）在较冷（16°C）与较暖（25°C）发育条件下，脂质饱和度（双键数量）的变化。与在恒定环境中进化的果蝇相比，在可变环境中进化的果蝇具有更大的能力来适应 PE/PC 比率，这支持了这样一种预测，即具有较高代际方差的环境有利于更大的发育可塑性。我们的结果与具有相关成本的更具环境敏感性等位基因的选择优势一致，这种等位基因在恒定环境中可能存在。
