In many species, temperature-sensitive phenotypic plasticity (i.e., an individual's phenotypic response to temperature) displays a positive correlation with latitude, a pattern presumed to reflect local adaptation. This geographical pattern raises two general questions: (a) Do a few large-effect genes contribute to latitudinal variation in a trait? (b) Is the thermal plasticity of different traits regulated pleiotropically? To address the questions, we crossed individuals of Plantago lanceolata derived from northern and southern European populations. Individuals naturally exhibited high and low thermal plasticity in floral reflectance and flowering time. We grew parents and offspring in controlled cool- and warm-temperature environments, mimicking what plants would encounter in nature. We obtained genetic markers via genotype-by-sequencing, produced the first recombination map for this ecologically important nonmodel species, and performed quantitative trait locus (QTL) mapping of thermal plasticity and single-environment values for both traits. We identified a large-effect QTL that largely explained the reflectance plasticity differences between northern and southern populations. We identified multiple smaller-effect QTLs affecting aspects of flowering time, one of which affected flowering time plasticity. The results indicate that the genetic architecture of thermal plasticity in flowering is more complex than for reflectance. One flowering time QTL showed strong cytonuclear interactions under cool temperatures. Reflectance and flowering plasticity QTLs did not colocalize, suggesting little pleiotropic genetic control and freedom for independent trait evolution. Such genetic information about the architecture of plasticity is environmentally important because it informs us about the potential for plasticity to offset negative effects of climate change.

中文翻译：

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两个繁殖性状显示了在车前草中不同的遗传结构。

在许多物种中，对温度敏感的表型可塑性（即一个人对温度的表型反应）与纬度呈正相关，推测是反映局部适应性的一种模式。这种地理格局提出了两个普遍的问题：（a）一些大效应基因是否会导致性状的纬度变异？（b）各种特性的热可塑性受到多效性调节吗？为了解决这些问题，我们对来自欧洲北部和南部人口的车前草个体进行了杂交。个体自然在花的反射率和开花时间上表现出高和低的热可塑性。我们在受控的凉爽和温暖的环境中长大了父母和后代，模仿了自然界中植物会遇到的情况。我们通过基因型测序获得了遗传标记，产生了该生态学上重要的非模型物种的第一个重组图，并对这两个性状进行了热可塑性和单环境值的定量性状基因座（QTL）作图。我们确定了一个有效的QTL，该QTL在很大程度上解释了北部和南部种群之间反射率可塑性的差异。我们确定了影响开花时间各个方面的多个较小影响的QTL，其中之一影响开花时间的可塑性。结果表明开花的热可塑性的遗传结构比反射的更为复杂。一个开花时间的QTL在凉爽的温度下显示出强烈的细胞核相互作用。反射率和开花可塑性QTL没有共定位，表明很少有多效性遗传控制和独立性状进化的自由。