Data from: Disentangling the role of phenotypic plasticity and genetic divergence in contemporary ecotype formation during a biological invasion

The occurrence of contemporary ecotype formation through adaptive divergence of populations within the range of an invasive species typically requires standing genetic variation but can be facilitated by phenotypic plasticity. The relative contributions of both of these to adaptive trait differentiation have rarely been simultaneously quantified in recently diverging vertebrate populations. Here we study a case of intraspecific divergence into distinct lake and stream ecotypes of threespine stickleback that evolved in the past 140 years within the invasive range in Switzerland. Using a controlled laboratory experiment with full-sib crosses and treatments mimicking a key feature of ecotypic niche divergence, we test if the phenotypic divergence that we observe in the wild results from phenotypic plasticity or divergent genetic predisposition. Our experimental groups show qualitatively similar phenotypic divergence as those observed among wild adults. The relative contribution of plasticity and divergent genetic predisposition differs among the traits studied, with traits related to the biomechanics of feeding showing a stronger genetic predisposition, whereas traits related to locomotion are mainly plastic. These results implicate that phenotypic plasticity and standing genetic variation interacted during contemporary ecotype formation in this case.入侵物种分布范围内，种群通过适应性分化形成当代生态型（ecotype）的过程，通常依赖于现存遗传变异，而表型可塑性（phenotypic plasticity）可促进这一过程。目前鲜有研究同时量化这两种因素对适应性性状分化的相对贡献，尤其是在新近分化的脊椎动物种群中。本研究聚焦于瑞士入侵分布区内、过去140年间演化形成的三刺鱼（threespine stickleback）种内分化案例——其分化为截然不同的湖泊与溪流生态型。本研究采用全同胞交配实验构建的受控实验室体系，并设置模拟生态型生态位分化关键特征的处理组，以验证野外观察到的表型分化究竟源于表型可塑性，还是分化的遗传倾向（genetic predisposition）。实验各组呈现的表型分化，与野生成体中观察到的模式在定性上高度一致。不同研究性状下，可塑性与分化遗传倾向的相对贡献存在差异：与摄食生物力学相关的性状表现出更强的遗传倾向，而与运动相关的性状则主要受表型可塑性调控。本研究结果表明，在该案例的当代生态型形成过程中，表型可塑性与现存遗传变异存在交互作用。