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

基因功能丧失是数量遗传性状对选择作出反应的一种机制，这是DG研究方案的基本前提。这一前提是基于在研究玉米玉米时所做的观察。)长期选择下的群体，建立在我的团队之前的研究基础上，并继续检查玉米数量性状背后的遗传结构。 这项提案将考察三个截然不同但又相互关联的假设。它们的不同之处在于它们涉及非常不同的特征--淀粉合成、果穗发育、叶片数量和开花时间。它们是相互联系的，因为它们涉及单基因功能等位基因的丧失，并可能参与改变分生组织的发育。具体地说：(1)短穗表型是通过积累和维持一组处于杂合状态的与穗发育有关的基因的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)，从而形成短穗表型。(2)直链淀粉延伸因子1修饰物(Mae1)是一种LOF突变，可产生较高水平的直链淀粉。(3)通过LOF突变的积累，可以选择基于叶片数和开花时间关系的改变的顶端分生组织(SAM)。 这项研究的影响既包括应用知识领域，也包括基础知识领域。它将作为2名理科硕士的训练场。学生，1名博士生，5名本科生。这将导致以玉米种质的形式开发新的知识产权，展示基于改变的基于SAM的叶数和开花时间的关系。

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.