Genetic Mechanisms Underlying Quantitative Traits in Maize - Dosage Effects & Loss of Function Mutations

基因功能的丧失是一种机制，通过这种机制，数量遗传性状对选择的反应是本DG研究建议的基本前提。这一前提是建立在对玉米（Zea mays L.）在长期选择下的群体，建立在我的小组以前的研究基础上，并继续研究玉米数量性状的遗传结构。本提案将审查三个不同但相互关联的假设。 它们的区别在于它们涉及非常不同的性状-淀粉合成，穗发育，叶片数量和开花时间。 它们是相关的，因为它们涉及功能等位基因的单基因缺失，并可能参与改变分生组织发育。 具体而言：（1）短穗表型是通过积累和维持一组杂合状态的参与穗发育的基因的LOF等位基因，从而有效地降低这些基因的表达水平（即，基因剂量）并导致短耳表型。(2)直链淀粉延伸物1的修饰物（mae 1）是赋予适度更高水平的直链淀粉的LOF突变。 (3)通过LOF突变的积累，将实现基于叶数和开花时间之间关系的改变的茎顶端分生组织（SAM）的选择。这项研究的影响是在应用和基础知识领域。 它将作为一个培训基地，2个硕士生，1个博士生。学生，5名本科生。 这将导致开发新的知识产权，以玉米种质的形式展示出改变的基于SAM的叶片数量和开花时间之间的关系。

Loss of gene function is a mechanism by which quantitatively inherited traits respond to selection is the underlying premise of this DG research proposal. This premise was built on observations made while working with a maize Zea mays L.) population under long-term selection, builds upon my group's previous research, and continues the examination of genetic architecture underlying quantitative traits in maize.**Three distinct yet interconnected hypotheses will be examined in this proposal. They are distinct in that they involve very different traits - starch synthesis, ear development, leaf number and flowering time. They are connected in that they involve single-gene loss of function alleles and are potentially involved in altering meristem development. Specifically: (1) The short-ear phenotype was achieved by accumulating & maintaining a set of LOF alleles for genes involved in ear development in a heterozygous state thus effectively reducing the level of expression of these genes (i.e., gene dosage) and resulting in a short-ear phenotype. (2) Modifier of amylose extender 1 (mae1) is a LOF mutation that confers a moderately higher level of amylose. (3) Selection for an altered shoot apical meristem (SAM) based relationship between leaf number and flowering time will be achieved through the accumulation of LOF mutations.**Impact of this research is both in the applied and basic knowledge arenas. It will serve as a training ground for 2 M.Sc. students, 1 Ph.D. student, and 5 undergraduate students. And it will lead to the development of novel intellectual property in the form of maize germplasm exhibiting altered SAM based relationship between leaf number and flowering time.