Experimental evolution of local adaptation under unidimensional and multidimensional selection.
Experimental evolution of local adaptation under unidimensional and multidimensional selection.
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一维和多维选择下局部适应的实验演化。
DOI：
10.1016/j.cub.2022.01.048
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
White NJ
中科院分区：
文献类型：
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作者：
White NJ
局部适应是产生生物多样性并可能促进生态物种形成的基本进化过程。发散选择通过推动空间结构种群的适应达到局部最优，成为局部适应进化的基础。环境很少只在一个环境轴上有所不同；因此，发散选择往往可能是多维的。发散选择的维度如何影响局部适应尚不清楚：进化理论预测，当与更强的整体选择相关时，增加维度将增加局部适应，但如果选择强度相等，则可能具有不太可预测的效果。需要进行实验来独立于选择的总强度来测试选择的维度对局部适应的影响。我们在单维发散选择（一对应激源）或多维发散选择（三对应激源）下实验进化了 32 对单角轮虫种群，保持处理之间选择的总强度相等。我们定期检测主场和客场环境的健康状况，以评估当地的适应情况。我们观察到，暴露于多维选择的种群中，局部适应能力最初增加，随后下降，而暴露于单维选择的种群中，局部适应能力的增加较慢，但最终更强。我们的结果与现有的预测形成对比，例如“弱杂项”和“强选择”假设。相反，我们假设对多维发散选择的适应可能有利于通才基因型，并且只产生短暂的局部适应。
Local adaptation is a fundamental evolutionary process generating biological diversity and potentially enabling ecological speciation. Divergent selection underlies the evolution of local adaptation in spatially structured populations by driving their adaptation toward local optima. Environments rarely differ along just one environmental axis; therefore, divergent selection may often be multidimensional. How the dimensionality of divergent selection affects local adaptation is unclear: evolutionary theory predicts that increasing dimensionality will increase local adaptation when associated with stronger overall selection but may have less predictable effects if selection strengths are equal. Experiments are required that allow the effect of the dimensionality of selection on local adaptation to be tested independently of the total strength of selection. We experimentally evolved 32 pairs of monogonont rotifer populations under either unidimensional divergent selection (a single pair of stressors) or multidimensional divergent selection (three pairs of stressors), keeping the total strength of selection equal between treatments. At regular intervals, we assayed fitness in home and away environments to assess local adaptation. We observed an initial increase and subsequent decline of local adaptation in populations exposed to multidimensional selection, compared with a slower but eventually stronger increase in local adaptation in populations exposed to unidimensional selection. Our results contrast with existing predictions, such as the "weak multifarious" and "stronger selection" hypotheses. Instead, we hypothesize that adaptation to multidimensional divergent selection may favor generalist genotypes and only produce transient local adaptation.