Institut de Biologie de l'École Normale Supérieure, CNRS UMR 8197, Inserm U1024, PSL Research University, Paris, France.
Elife. 2023 Aug 31;12:e80993. doi: 10.7554/eLife.80993.
Predicting adaptive phenotypic evolution depends on invariable selection gradients and on the stability of the genetic covariances between the component traits of the multivariate phenotype. We describe the evolution of six traits of locomotion behavior and body size in the nematode for 50 generations of adaptation to a novel environment. We show that the direction of adaptive multivariate phenotypic evolution can be predicted from the ancestral selection differentials, particularly when the traits were measured in the new environment. Interestingly, the evolution of individual traits does not always occur in the direction of selection, nor are trait responses to selection always homogeneous among replicate populations. These observations are explained because the phenotypic dimension with most of the ancestral standing genetic variation only partially aligns with the phenotypic dimension under directional selection. These findings validate selection theory and suggest that the direction of multivariate adaptive phenotypic evolution is predictable for tens of generations.
预测适应性表型进化取决于不变的选择梯度，以及多元表型组成性状之间遗传协方差的稳定性。我们描述了线虫在适应新环境的 50 代过程中，六种运动行为和体型特征的进化。我们表明，从祖先的选择差异可以预测适应性多元表型进化的方向，特别是当这些性状在新环境中测量时。有趣的是，个别性状的进化并不总是朝着选择的方向进行，性状对选择的反应也不是在所有重复种群中都完全一致。这些观察结果可以解释为，只有部分祖先遗传变异的表型维度与定向选择下的表型维度完全一致。这些发现验证了选择理论，并表明在几十代的时间内，多元适应性表型进化的方向是可预测的。
