Dissertation Research: Genetic Basis of Flowering Date in Arabidopsis thaliana

生活史特征如生育力、初龄等 繁殖，与最终的生存密切相关， 植物的繁殖能力。 生活史特征直接 受到人工和自然选择的影响，因此， 特别关注植物育种者和进化 生物学家一样。 这些特征的表达被认为是 是许多影响小的基因（数量性状）的结果 基因座或QTL）。 预测的速度和方向 进化变化取决于分离QTL的数量， 其影响的大小。 QTL的实际数目 参与数量变化，重要性和 大效应QTL的普遍性实际上仍然是未知的。 基于统计理论的方法已被用于估计 影响一个性状的QTL的最小数目， 它们的影响程度，但这些方法缺乏精确性。 在 对比，分子生物学技术和经典的 数量遗传学提供了一种强有力的手段， QTL的最小数目及其相对效应。 本研究将利用拟南芥的遗传标记， 回答以下问题：1）有多少个QTL控制着 开花的时间？2)有没有影响力大的基因？ 3)做 开花期与其他性状的互作 对植物生存很重要的是， 在开花时间的进化中起着重要作用 拟南芥 是这项研究的理想生物，因为现有的地图 非常完整。 自然发生的 自交系极大地简化了统计分析。 这些 技术已经成功地用于标记辅助选择 一些作物重要经济性状的项目。 它们也是基因改良计划中的有力工具 来解决基本的进化和遗传问题。 然而，这些技术尚未应用于天然植物 人口。 这项工作将提供一些第一批数据， 基因的数量和遗传效应的大小 物种

Life history characters such as fecundity and age at first reproduction, are closely related to the ultimate survival and reproductive ability of plants. Life history traits are directly affected by artificial and natural selection and are therefore of particular concern for both plants breeders and evolutionary biologists alike. The expression of these traits is thought to be the result of many genes of small effect (quantitative trait loci or QTLs). Predictions about the rate and direction of evolutionary change depend on the number of segregating QTLs and the magnitude of their effects. The actual number of QTLs involved in quantitative variation, and the importance and prevalence of QTLs of large effect is still virtually unknown. Methods based on statistical theory have been used to estimate the minimum number of QTLs influencing a trait, and the relative magnitude of their effects, but these methods lack precision. In contrast, techniques of molecular biology and classical quantitative genetics provide a powerful means of estimating the minimum number of QTLs and their relative effects. This study will use genetic markers in Arabidopsis thaliana to answer the following questions: 1) How many QTLs control the timing of flowering? 2) Are there genes of large effect? 3) Do interactions between flowering time and other characters important to plant survival prevent genes of large effect from being important in the evolution of flowering time? Arabidopsis is the ideal organism for this study because the existing map is extraordinarily complete. The existence of naturally occurring inbred lines greatly simplifies statistical analyses. These techniques have been used with success in marker-aided selection programs for economically important traits in a few crop plants. They are powerful tools in genetic improvement programs, as well as for addressing fundamental evolutionary and genetic questions. However, these techniques have not been applied to natural plant populations. This work will provide some of the first data on the number of genes and the magnitude of genetic effects within species.