Optimal Reaction Norms and Genetic Constraints in the Evolution of Plant Size in Ipomoea purpurea

紫薯株型演化的最优反应规范和遗传约束

• 批准号: 9707223
• 负责人: Mark Rausher
• 金额: $ 32.99万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9707223&HistoricalAwards=false
• 关键词: Optimal; Reaction; Norms; Genetic; Constraints

9707223 Rausher The goal of this project is to attempt to understand the degree to which a model organism, the morning glory Ipomorea purpurea, is optimally adapted to various environments it encounters. Specifically, this project seeks to characterize empirically the optimal value for several traits in different environments and then determine whether natural populations have evolved to exhibit those values in the respective environments. The project also seeks to characterize any constraints that may prevent populations from evolving to those optimal values. Characteristics of the range of natural environments normally encountered by I. purpurea will initially be surveyed. Using this information, two field experiments will be conducted in which I. purpurea is grown either a gradient of soil nutrient levels or a gradient of competitive intensity. The pattern of natural selection acting on traits related to plant growth and size will be measured to determine how far the means of these traits are from their optima in each environment. A set of breeding and selection experiments will provide a characterization of any genetic constraints acting to prevent evolution toward these optima, and the importance of these constraints will be evaluated by computer simulation. Evolution by natural selection is a compromise between what is favored (how selection acts) and what is possible (determined by the genetics of organisms). While biologists have made great strides understanding evolution in model organisms (e.g. fruit flies) living in simple, controlled environments, much less is known about the evolutionary responses of plant and animal populations to complex natural environments. The broad aim of this project is to begin to provide an understanding of such a response in an organism that typically encounters a complex environment.

9707223 Rausher 该项目的目标是尝试了解模式生物（牵牛花 Ipomorea purpurea）对其所遇到的各种环境的最佳适应程度。 具体来说，该项目旨在凭经验描述不同环境中几种性状的最佳值，然后确定自然种群是否已经进化到在各自的环境中表现出这些值。 该项目还试图描述可能阻止种群进化到这些最佳值的任何限制因素。 首先将调查 I. purpurea 通常遇到的自然环境范围的特征。 利用这些信息，将进行两项田间实验，其中紫花紫藤按照土壤养分水平梯度或竞争强度梯度进行种植。 将测量作用于与植物生长和大小相关的性状的自然选择模式，以确定这些性状的平均值与其在每种环境中的最佳值的距离。 一组育种和选择实验将提供阻止向这些最佳状态进化的任何遗传约束的特征，并且这些约束的重要性将通过计算机模拟进行评估。 自然选择的进化是有利的（选择如何发挥作用）和可能的（由生物体的遗传学决定）之间的折衷。虽然生物学家在了解生活在简单、受控环境中的模式生物（例如果蝇）的进化方面取得了长足的进步，但对植物和动物种群对复杂自然环境的进化反应知之甚少。 该项目的主要目标是开始了解通常遇到复杂环境的生物体中的这种反应。