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 (PST and QST). With individual-based simulations, we tested our model predictions and further modeled allelic differentiation at neutral (FST) and adaptive (FSTQ) 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.

诸多演化进程共同塑造了种群的遗传与表型分化。其中，基因流、选择与表型可塑性（phenotypic plasticity）的联合效应尚未得到充分阐明，尤其是在探究适应不良可塑性如何影响种群分化的场景中。我们拓展了Hendry等人（2001）提出的数量遗传模型，用以刻画这三类因素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指数（PST）与数量性状遗传分化指数（QST）的联合效应。我们通过基于个体的模拟（individual-based simulations）检验了模型预测结果，并进一步对中性位点（FST）与适应性位点（FSTQ）的等位基因分化开展了建模。尽管适应性表型可塑性可在高基因流条件下促成显著的表型分化与分化水平，但适应不良的可塑性会推动遗传分化并产生反梯度变异（countergradient variation）；在大规模迁移场景中，表型差异有时会与遗传差异相悖。适应不良的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，可塑性会打破种群间遗传差异与表型差异之间的耦合关系，模糊表型分化与局部适应（local adaptation）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，进一步阐明了物种种群生态对结构化种群（structured populations）演化的影响。