Data from: The role of phenotypic plasticity on population differentiation

Several evolutionary processes shape the genetic and phenotypic differentiation of populations. Among them, the joint effects of gene flow, selection, and phenotypic plasticity are poorly known, especially when trying to understand how maladaptive plasticity affects population divergence. We extended a quantitative genetic model of Hendry et al. (2001) to describe these joint effects on phenotypic and additive genetic divergence between two populations, and their phenotypic and genetic differentiation (P_ST and Q_ST). With individual-based simulations we tested our model predictions and further modeled allelic differentiation at neutral (F_ST) and adaptive (F_STQ) loci. While adaptive phenotypic plasticity allows for large phenotypic divergence and differentiation despite high gene flow, maladaptive plasticity promotes genetic divergence and generates countergradient variation, under extensive migration with phenotypic differences sometimes opposed to genetic differences. Maladaptive plasticity can also promote adaptive phenotypic divergence by reducing the effective gene flow. Overall, plasticity decouples genetic from phenotypic differences between populations, and blurs the correlation between phenotypic divergence and local adaptation. By deriving models of population differentiation for three different life cycles, we further describe the effect of a species' ecology on evolution in structured populations.

多种进化过程共同塑造了种群的遗传与表型分化。在这些过程中，基因流（gene flow）、自然选择与表型可塑性（phenotypic plasticity）的联合效应仍未得到充分阐释，尤其是在尝试解析适应不良表型可塑性（maladaptive plasticity）如何影响种群分化这一问题时。我们拓展了亨德利等人（Hendry et al., 2001）提出的定量遗传模型，用以描述上述三者对两个种群间表型分化与加性遗传分化，以及二者的表型分化（P_ST）和遗传分化（Q_ST）的联合效应。我们通过基于个体的模拟（individual-based simulations）验证了模型预测，并进一步针对中性位点（F_ST）与适应性位点（F_STQ）的等位基因分化情况开展建模分析。研究结果显示，尽管高基因流会抑制分化，但适应性表型可塑性仍可促成显著的表型分化与分化水平提升；而适应不良表型可塑性则会推动遗传分化并产生反梯度变异（countergradient variation）：在大规模迁移场景下，种群间的表型差异有时会与遗传差异相悖。此外，适应不良表型可塑性还可通过降低有效基因流，促进适应性表型分化。总体而言，表型可塑性会使种群间的遗传差异与表型差异解耦，模糊表型分化与局部适应之间的相关性。我们还针对三种不同生活史周期推导了种群分化模型，进一步阐明了物种生态学特征对结构化种群演化过程的影响。