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 trajectorie...

尽管物种适应温暖气候的潜力受限于遗传权衡（genetic trade-offs），但目前学界对于选择与突变如何塑造热反应规范（thermal reaction norms）中的遗传（共）方差的认知仍较为匮乏。本研究以采自欧洲北部、中部与南部不同气候区域的71个单雌系（isofemale lines）黑点粪蝇（*Sepsis punctum*）为实验材料，在5个不同实验温度下，检测了幼体发育速率随纬度梯度的分化情况。为探究不同气候环境下的演化历史对热反应规范中现有遗传变异的影响，我们进一步比较了不同地理区域间的遗传（共）方差。我们设置高、低两种食物资源条件饲养该蝇类，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，这表明热反应规范的演化将通过不同的路径推进……