MUTATION, DRIFT, & THE RATE OF PHENOTYPIC EVOLUTION

这一项目关注的是对 表型进化的速度，特别是与 突变和随机遗传漂移。最近的理论工作已经 阐明了多基因突变的重要贡献 对自交系的分化，对长期的反应 定向选择方案，并保持遗传 稳定选择下的变异。然而，实际情况是 这一理论的实用性因缺乏严谨而受到严重限制。 关于多基因突变特性的信息。使用三个 模式系统(微型甲壳类水蚤、蜗牛淋巴和 玉米)，我们计划启动长期的突变积累 实验目的是：1)获得突变的估计值 遗传方差的投入率(Vm)和显性程度 新突变的多效性效应，以及2)检验假设 多基因突变率取决于世代时间， 减数分裂频率、性状表现年龄和遗传 背景资料。提议的物种和实验方案有 是专门选择的，以避免出现 破坏了之前测量多基因的性质的尝试 并帮助揭示现有的对VM的估计是否 有偏见。结合实证工作，分析和 将进行数值研究，以便开发 计入联合作用的数量遗传模型 有限的种群规模、多基因突变和选择。这个 理论预测对显性、连锁、 多效性将会被评估。长远的现实目标 研究的目的是提供必要的定量信息 TO：1)预测无性和纯合子的预期稳定性 正越来越多地在生物医学中使用的生产线 研究，2)确定长期选择的最优设计 计划和遗传保护计划。

This project is concerned with the long-term constraints on the rate of phenotypic evolution, particularly with the interaction of mutation and random genetic drift. Recent theoretical work has clarified the important contribution that polygenic mutation makes to the divergence of inbred lines, the response to long-term directional selection programs, and the maintenance of genetic variation under stabilizing selection. However, the practical utility of this theory is severely limited by a lack of rigorous. information on the properties of polygenic mutation. Using three model systems (the microcrustacean Daphnia, the snail Lymnaea, and corn), we plan to initiate long-term mutation-accumulation experiments in order to: 1) obtain estimates for the mutational rate of input of genetic variance (VM) and extent of dominance and pleiotropic effects of new mutations, and 2) test the hypotheses that the rate of polygenic mutation depends on generation time, frequency of meiosis, age of expression of characters, and genetic background. The proposed species and experimental protocols have been specifically selected in order to avoid the problems that have marred previous attempts to measure the properties of polygenic mutation and to help reveal whether existing estimates of VM are biased. In conjunction with the empirical work, analytical and numerical studies will be performed in order to develop quantitative genetic models that incorporate the joint interaction of finite population size, polygenic mutation, and selection. The sensitivity of the theoretical predictions to dominance, linkage, and pleiotropy will be evaluated. The long-term practical goals of the study are to provide the quantitative information necessary to: 1) predict the expected stability of asexual and homozygous lines that are becoming increasingly utilized in biomedical research, 2) determine the optimal designs of long-term selection programs and genetic conservation programs.