Genomic Analysis of Complex Trait Variation in Mimulus

描述(申请人提供)：种群遗传学的一个主要目标是确定遗传变异的性质以及如何在自然种群中保持这种变异。点滴菊是一种野花，在花朵大小上表现出很大的遗传变异，这一特征在物种复合体中已经广泛进化。我们将在单个自然种群中定位导致花朵大小变化的遗传位点，并确定等位基因对一系列植物性状的影响的大小和分布。这些实验将估计QTL的显性程度和模式，以及与花朵大小等位基因相关的多效性效应。简化的育种计划将产生近等基因系(NILs)，这是对定义重要QTL的实际基因座进行定位克隆所必需的。它们还将用于田间和实验室研究，以在单个QTL的尺度上衡量花朵大小变异的直接适合性结果。这些数据将被用来检验关于选择性维持花朵大小变异的假设。结合以前和正在进行的研究的结果，这些实验将提供一个详细的比较，在种间和种内的花朵形态的变异在舌状根的物种复合体内。重要花卉QTL的定位克隆将使生态重要基因的分子群体遗传学研究成为可能。拟议的研究将通过教育和科学资源的开发产生更广泛的影响。

DESCRIPTION (provided by applicant): A primary objective of population genetics is to determine the nature of genetic variation and how it is maintained in natural populations. Mimulus guttatus is a wildflower that exhibits substantial genetic variation in flower size, a trait that has evolved extensively within the species complex. We will map the genetic loci responsible for variation in flower size within a single natural population of M. guttatus and determine the magnitude and distribution of allelic effects on a range of plant characters. The experiments will estimate the extent and pattern of dominance at QTL and the pleiotropic effects associated with flower size alleles. A streamlined breeding scheme will produce Nearly Isogenic Lines (NILs), necessary for positional cloning of the actual loci defining important QTL. They will also be used in field and lab studies to measure the direct fitness consequences of flower size variation at the scale of individual QTL. These data will be used to test hypotheses regarding the selective maintenance of flower size variation. Combined with results from previous and ongoing studies, these experiments will provide a detailed comparison of inter- and intra- specific variation in floral morphology within the M. guttatus species complex. Positional cloning of important floral QTLs will allow molecular population genetic studies of ecologically important genes. The proposed research will have broader impacts thorough both education and the development of scientific resources.