Am Nat. 2021 Jan;197(1):29-46. doi: 10.1086/711874. Epub 2020 Nov 25.
AbstractDetecting contemporary evolution requires demonstrating that genetic change has occurred. Mixed effects models allow estimation of quantitative genetic parameters and are widely used to study evolution in wild populations. However, predictions of evolution based on these parameters frequently fail to match observations. Here, we applied three commonly used quantitative genetic approaches to predict the evolution of size at maturity in a wild population of Trinidadian guppies. Crucially, we tested our predictions against evolutionary change observed in common-garden experiments performed on samples from the same population. We show that standard quantitative genetic models underestimated or failed to detect the cryptic evolution of this trait as demonstrated by the common-garden experiments. The models failed because (1) size at maturity and fitness both decreased with increases in population density, (2) offspring experienced higher population densities than their parents, and (3) selection on size was strongest at high densities. When we accounted for environmental change, predictions better matched observations in the common-garden experiments, although substantial uncertainty remained. Our results demonstrate that predictions of evolution are unreliable if environmental change is not appropriately captured in models.
摘要 要检测当代进化，就必须证明遗传变化已经发生。混合效应模型允许估计数量遗传参数，并广泛用于研究野生种群的进化。然而，基于这些参数的进化预测经常与观察结果不符。在这里，我们应用了三种常用的定量遗传方法来预测特立尼达鳉鱼野生种群成熟大小的进化。至关重要的是，我们根据来自同一群体的样本进行的常见花园实验中观察到的进化变化来检验我们的预测。我们表明，标准的定量遗传模型低估或未能检测到这种特征的隐性进化，正如常见花园实验所证明的那样。这些模型失败的原因是：（1）成熟大小和适应性都随种群密度的增加而降低；（2）后代经历的种群密度高于其父母；（3）在高密度下，对大小的选择最强。当我们考虑到环境变化时，预测与常见花园实验中的观察结果更加吻合，尽管仍然存在很大的不确定性。我们的结果表明，如果模型不能适当捕捉环境变化，进化预测是不可靠的。
