Evolutionary adaptation to intensifying drought across a geographic gradient: a comprehensive evaluation of Fisher's Fundamental Theorem

该项目将通过调查一种原产于加州的野生开花植物（通常被称为婴儿蓝眼睛）对干旱加剧的适应率，来测试长期存在的进化理论，即种群能够以多快的速度适应不断变化的环境。种群适应压力环境条件的能力取决于生存和繁殖中存在的遗传变异，以及影响生存和繁殖的性状（如植物生理学和繁殖时间）的遗传变异。 很少有研究测量适应过程，以确定决定植物种群如何快速适应自然界中水分有限条件的因素。这项研究将整合以下措施：（1）植物生存和繁殖的遗传变异，包括自然种群内和自然种群之间的遗传变异，以及有助于植物表现的性状;（2）野生种群的自然选择;（3）生存和繁殖遗传方面的代际变化。 将使用基于进化理论的统计模型来预测每个研究群体中应发生的适应性变化的幅度。 这些预测将与世代之间观察到的生存和繁殖的实际变化进行比较。代表性不足的群体的本科生将被招募参加这项研究，通过美国生态学会，美国印第安人科学与工程学会，以及科学促进奇卡诺人和美洲土著人的社会。这些学生将接受设计，实施和分析从田间和育种实验中收集的遗传数据的培训。将与部落社区的环境和土地部门建立合作关系，并向当地社区提供研讨会，告知他们这项研究的目标，方法和成果。许多植物物种的研究已经发现物候或形态性状对实验诱导或自然环境变化的可塑性反应，或在不同环境中的群体中表型选择的强度或方向的变化。 然而，迄今为止，没有研究评估进化的变化代之间，在真实的时间，跨越自然环境梯度方面的物候，形态和生理特征。本研究将联合收割机的详细研究，在广泛分布的草本植物（Nemophila menziesii，Hydrophyllaceae）的人口之间的适应性相关性状的地理变异与措施：表型选择的性状，有助于耐旱性;代际变化的加性遗传方差的健身;和选择，以测试预测适应环境条件下的干旱梯度。Aster模型将用于估计田间条件下家系群体中个体适合度的加性遗传方差，并估计物候、形态和生理性状选择的强度和方向。这些模型将有利于经验评估的准确性，费舍尔的自然选择基本定理（FFT），预测的变化率在人口平均健身应等于比率的加性遗传方差的健身平均绝对健身。这一比率代表人口适应当前条件的能力，或其“适应能力”。 该项目将是第一个严格的评估FFT在野生种群跨越环境梯度。这项研究将有助于理解自然选择如何在一个物种的范围内运作，可能识别机制，如存在多种组合的特征与健身最佳，促进野生种群的遗传变异的维护。

This project will test long-standing evolutionary theory about how rapidly populations can adapt to changing environments by investigating rates of adaptation to intensifying drought in a wild, flowering plant native to California, commonly known as baby blue eyes. The ability of populations to adapt to stressful environmental conditions depends on the presence of genetic variation in survival and reproduction, as well as a genetic variation in the traits that affect survival and reproduction, such as plant physiology and timing of reproduction. Very few studies have measured the process of adaptation to identify the factors that determine how rapidly plant populations adapt to water-limited conditions, in nature. This research will integrate measures of: (1) genetic variation in plant survival and reproduction, both within and among natural populations, as well as in the traits that contribute to plant performance; (2) natural selection in wild populations; and (3) changes between generations in the genetically based aspects of survival and reproduction. Statistical models based on evolutionary theory will be used to predict the magnitude of adaptive change that should occur in each study population. These predictions will be compared to the actual change in survivoral and reproduction observed between generations. Undergraduate students in under-represented groups will be recruited to participate in this research through the Ecological Society of America, the American Indian Science and Engineering Society, and the Society for the Advancement of Chicano and Native Americans in Science. These students will be trained in the design, implementation, and analysis of genetic data collected from field and breeding experiments. Cooperative relationships will be built with the Environmental and Lands departments of Tribal communities, and workshops will be offered to local communities to inform them of the goals, methods, and outcomes of this research.Many studies of plant species have detected plastic responses of phenological or morphological traits to experimentally induced or natural environmental variation, or changes in the strength or direction of phenotypic selection in populations occupying different environments. To date, however, no studies have assessed evolutionary change between generations, in real time, across natural environmental gradients with respect to phenological, morphological, and physiological traits. This study will combine detailed studies of geographic variation in fitness-related traits among populations of a widespread herb (Nemophila menziesii, Hydrophyllaceae) with measures of: phenotypic selection on traits that contribute to drought-tolerance; inter-generational change in additive genetic variance in fitness; and the response to selection in order to test predictions regarding adaptation to environmental conditions across an aridity gradient. Aster models will be used to estimate additive genetic variance in individual fitness in pedigreed populations under field conditions and to estimate the strength and direction of selection on phenological, morphological, and physiological traits. These models will facilitate the empirical evaluation of the accuracy of Fisher's Fundamental Theorem of Natural Selection (FFT), which predicts that the rate of change in population mean fitness should equal the ratio of additive genetic variance in fitness to mean absolute fitness. This ratio represents a population's capacity to adapt to current conditions, or its "adaptive capacity". This project will be the first rigorous evaluation of FFT in wild populations across an environmental gradient. This study will contribute to the understanding of how natural selection operates across a species' range, potentially identifying mechanisms, such as the existence of multiple combinations of traits associated with fitness optima, that promote the maintenance of genetic variation in wild populations.