Several empirical studies report fast evolutionary changes in flowering time in response to contemporary climate change. Flowering time is a polygenic trait under assortative mating, since flowering time of mates must overlap. Here, we test whether assortative mating, compared with random mating, can help better track a changing climate. For each mating pattern, our individual-based model simulates a population evolving in a climate characterized by stabilizing selection around an optimal flowering time, which can change directionally and/or fluctuate. We also derive new analytical predictions from a quantitative genetics model for the expected genetic variance at equilibrium, and its components, the lag of the population to the optimum and the population mean fitness. We compare these predictions between assortative and random mating, and to our simulation results. Assortative mating, compared with random mating, has antagonistic effects on genetic variance: it generates positive associations among similar allelic effects, which inflates the genetic variance, but it decreases genetic polymorphism, which depresses the genetic variance. In a stationary environment with substantial stabilizing selection, assortative mating affects little the genetic variance compared with random mating. In a changing climate, assortative mating however increases genetic variance compared to random mating, which diminishes the lag of the population to the optimum, and in most scenarios translates into a fitness advantage relative to random mating. The magnitude of this fitness advantage depends on the extent to which genetic variance limits adaptation, being larger for faster environmental changes and weaker stabilizing selection.

中文翻译：

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分类交配可以帮助开花时间适应不断变化的气候：来自多基因模型的见解。

一些实证研究报告了开花时间的快速进化变化，以应对当代气候变化。开花时间是组合交配下的多基因性状，因为配偶的开花时间必须重叠。在这里，我们测试了与随机交配相比，分类交配是否有助于更好地追踪气候变化。对于每种交配模式，我们基于个体的模型模拟了种群在气候中的进化，其特征是在最佳开花时间附近稳定选择，该开花时间可以方向变化和/或波动。我们还从定量遗传学模型中推导出新的分析预测，以了解平衡时的预期遗传方差及其组成部分、种群到最优的滞后和种群平均适应度。我们比较了分类交配和随机交配之间的这些预测，以及我们的模拟结果。与随机交配相比，分类交配对遗传变异具有拮抗作用：它在相似的等位基因效应之间产生正相关，从而扩大了遗传变异，但它降低了遗传多态性，从而抑制了遗传变异。在具有大量稳定选择的静止环境中，与随机交配相比，分类交配对遗传变异的影响很小。然而，在不断变化的气候中，与随机交配相比，分类交配会增加遗传变异，从而将种群的滞后减少到最佳状态，并且在大多数情况下转化为相对于随机交配的适应性优势。这种适应度优势的大小取决于遗传变异限制适应的程度，