Data from: Quantitative genetic divergence and standing genetic (co)variance in thermal reaction norms along latitude

Although the potential to adapt to warmer climate is constrained by genetic trade-offs, our understanding of how selection and mutation shape genetic (co)variances in thermal reaction norms is poor. Using 71 isofemale lines of the fly Sepsis punctum, originating from northern, central and southern European climates, we tested for divergence in juvenile development rate across latitude at five experimental temperatures. To investigate effects of evolutionary history in different climates on standing genetic variation in reaction norms, we further compared genetic (co)variances between regions. Flies were reared on either high or low food resources to explore the role of energy-acquisition in determining genetic trade-offs between different temperatures. Although the latter had only weak effects on the strength and sign of genetic correlations, genetic architecture differed significantly between climatic regions, implying that evolution of reaction norms proceeds via different trajectories at high versus low latitude in this system. Accordingly, regional genetic architecture was correlated to region-specific differentiation. Moreover, hot development temperatures were associated with low genetic variance and stronger genetic correlations compared to cooler temperatures. We discuss the evolutionary potential of thermal reaction norms in light of their underlying genetic architectures, evolutionary histories and the materialization of trade-offs in natural environments.

尽管物种适应温暖气候的潜力受到遗传权衡（genetic trade-offs）的限制，但我们对选择与突变如何塑造热反应规范（thermal reaction norms）中的遗传（共）方差（genetic (co)variances）的认知仍十分有限。本研究以源自欧洲北部、中部与南部不同气候区域的71个单雌系（isofemale lines）的斑点扁脚蝇（Sepsis punctum）为实验材料，在5个实验温度下检测了其幼体发育速率沿纬度梯度的分化情况。为探究不同气候下的演化历史对反应规范中现存遗传变异的影响，我们进一步比较了不同地理区域间的遗传（共）方差。本研究将实验蝇类分别置于高、低两种食物资源条件下饲养，以探究能量获取在调控不同温度间遗传权衡中的作用。尽管食物资源条件对遗传相关的强度与方向仅存在微弱影响，但不同气候区域间的遗传架构（genetic architecture）却存在显著差异，这表明本研究体系中，热反应规范的演化在高纬度与低纬度区域遵循不同的轨迹。相应地，区域特有的遗传架构与该区域的种群分化显著相关。此外，相较于较低的发育温度，较高的发育温度与较低的遗传方差以及更强的遗传相关存在关联。最后，我们结合热反应规范背后的遗传架构、演化历史以及自然环境中权衡效应的具体表达，探讨了其演化潜力。