RUI: Quantifying and Interpreting Costs of Phenotypic Plasticity Using Recombinant Inbred Lines of Arabidopsis

物种内的变异反映了遗传和环境因素，而表型可塑性一词是指由环境变量可预测地触发的一个或多个性状的变异。温带一年生植物拟南芥将被用来调查暴露于越冬温度引发的开花时间的变化，强调开花时间的影响及其可塑性的健身。这些现象在拟南芥中被广泛研究，但生态实验尚未评估可塑性是否是适应性的，中性的，甚至是适应不良的。我们将解决两个问题，使用平行的实验室和现场实验环境模拟温和和严峻的冬天。第一，开花时间是否存在自然选择及其可塑性？我们将量化环境中的可塑性，并将环境中的适应性和开花时间相关联。然后，我们可以评估观察到的可塑性是否倾向于增加一个或两个环境中的适应性。第二，健康是否还与拥有可塑性的能力有关？这种相关性，如果是负的，被称为可塑性成本，并可能表明参与检测或响应环境的基因间接降低了适应性。理论模型表明，可塑性成本可以解释为什么适应性表型可塑性既不是最佳的，也不是普遍的。使用拟南芥，这将是劳动密集型的，但可行的进行大的，良好的复制实验室和田间实验中，开花时间和健身评分。开花时间有广泛的自然变异，一些菌株具有极强的可塑性，而另一些则很少或没有。参与调控开花时间可塑性的主要基因在许多菌株中具有特征，对比菌株的杂交产生了几个实验种群，现在可以很容易地提供给拟南芥研究人员。我们选择了其中的几个进行实验。这些群体所具有的变异性将增强我们检测自然选择和可塑性代价的能力，并将可塑性及其代价与潜在的遗传机制联系起来。拟议中的研究将在巴纳德学院进行，这是一所隶属于纽约市哥伦比亚大学的女子文理学院，终身教职过程将教师作为教师学者进行评估，他们可以在课堂上表现出色，同时也可以进行涉及本科生的高素质研究。拟议的项目符合这些标准。此外，通过在女教师的实验室工作，暑期学生实习生和学生员工将获得在自然科学事业成功所需的重要技能，指导和鼓励。在科学中代表性不足的群体在巴纳德的学生中有很好的代表性，并且以前在PI的实验室接受过培训。

Variation within species reflects both genetic and environmental factors, and the term phenotypic plasticity refers to variation in one or more traits predictably triggered by an environmental variable. The temperate annual plant species Arabidopsis thaliana will be used to investigate variation in flowering time triggered by exposure to over-wintering temperatures, emphasizing the impact of flowering time and its plasticity on fitness. These phenomena are widely studied in Arabidopsis, but ecological experiments have not yet assessed whether plasticity is adaptive, neutral, or perhaps even maladaptive. We will address two questions using parallel lab and field experiments in environments mimicking mild and severe winters. First, is there natural selection on flowering time and its plasticity? We will quantify plasticity across environments and correlate fitness and flowering time within environments. We can then assess whether the observed plasticity tends to increase fitness within one or both environments. Second, is fitness additionally correlated with possessing the ability to be plastic? Such a correlation, if negative, is referred to as a plasticity cost and may indicate that the genes involved in detecting or responding to the environment indirectly reduce fitness. Theoretical models indicate that plasticity costs can explain why adaptive phenotypic plasticity is neither optimal nor universal. Using Arabidopsis, it will be labor-intensive but feasible to conduct large, well-replicated lab and field experiments in which flowering time and fitness are scored. There is extensive natural variation for flowering time, with some strains possessing extreme plasticity, and others little or none. Major genes involved in regulating flowering time plasticity have characterized in many strains, and hybridization of contrasting strains has yielded several experimental populations now readily available to Arabidopsis researchers. We have selected several of these for our experiments. The variability harbored by these populations will enhance our ability to detect natural selection and plasticity costs, and to relate plasticity and its costs to underlying genetic mechanisms. The proposed research will be conducted at Barnard College, a liberal arts college for women affiliated with Columbia University in New York City, where the tenure process evaluates faculty as teacher-scholars who can excel in the classroom while also conducting high caliber research that involves undergraduates. The projects proposed are consistent with these criteria. Moreover, by working in a female faculty member's lab, summer student interns and student employees will gain important skills, mentoring, and encouragement necessary for successful careers in the natural sciences. Groups underrepresented in the sciences are well represented in Barnard's student body and have previously received training in the PI's lab.