Dissertation Research: The Role of Floral Symmetry Genes in the Evolution of Stamen Development in Mohavea (Scrophulariaceae, Antirrhineae)

论文研究：花对称基因在莫哈维（玄参科、金鱼科）雄蕊发育进化中的作用

• 批准号: 9972647
• 负责人: Elena Kramer
• 金额: $ 0.94万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9972647&HistoricalAwards=false
• 关键词: Dissertation; Research; Role; Floral; Symmetry

9972647Baum and Hileman Recent studies focusing on model plant systems including the snapdragon Antirrhinum majus (family Scrophulariaceae) have identified individual genes affecting flower development, floral shape, and floral parts. Graduate student Lena Hileman, under the direction of Dr. David Baum at Harvard University, is investigating close relatives of the snapdragon in the genera Mohavea and Sairocarpus, to construct a molecular phylogeny of the species (mostly based on chloroplast ndhF sequences) in order to explore evolutionary changes in the floral development genes. The specific aim is to determine the genes that cause Mohavea flowers to have only two stamens as opposed to the four produced by snapdragon flowers. The search for the genetic basis of this difference is facilitated because a gene influencing stamen abortion, CYCLOIDEA (CYC), has been characterized in snapdragon. In snapdragon, CYC is expressed in one of the five stamen primordia and results in that stamen aborting (leaving four stamens to mature). Expression of CYC-like genes in the tetraploid Mohavea (where there may be multiple copies) will be studied in tissue preparations to see if these genes are expressed in early stages of the three aborted stamens. The work constitutes a fine-scale genetic dissection of the developmental control of floral characters used in the species- and genus-level classification of Scrophulariaceae plants. Because plants of Mohavea are tetraploid (contain two complete genomes), they are expected to possess two copies of CYC and two copies of a closely related gene, DICHOTOMA (DICH). The project will include DNA sequencing of the members of the CYC/DICH gene family in order to provide information regarding molecular evolutionary changes in this gene family. Preliminary work has already identified four potential gene products, thus providing material for sequence analysis to determine whether some of the genes have been subject to stronger natural selection (as indicated by reduced rates of molecular evolution). By combining a detailed understanding of the selective history of these genes with studies of gene expression patterns, we will learn about the fate of duplicate genes during genome evolution and their role in morphological diversification.

9972647baum and Hileman最近的研究重点是模型植物系统，包括Snapdragon抗rhinum Majus（家庭卷皮科），已经确定了影响花朵发育，花卉形状和花卉部分的单个基因。 在哈佛大学的戴维·鲍姆（David Baum）博士的指导下，研究生莉娜·希尔曼（Lena Hileman）正在调查莫哈维（Mohavea）和sairocarpus属的Snapdragon的近亲，以构建该物种的分子系统发育（主要基于叶绿体NDHF序列），以探索花卉发展基因的进化变化。具体的目的是确定导致莫哈维（Mohavea）花的基因只有两个雄蕊，而不是由Snapdragon花产生的四种雄蕊。 由于在Snapdragon中表征了影响雄蕊流产的基因，因此寻找这种差异的遗传基础。 在Snapdragon中，CYC在五个雄蕊原始中表达，并导致雄蕊流产（留下四个雄蕊成熟）。将在组织制剂中研究四倍体Mohavea（可能有多个副本）中CYC样基因的表达，以查看这些基因是否在三个流产的雄蕊的早期阶段表达。这项工作构成了对舒适性植物物种和属水平分类中花卉特征的发育控制的细构遗传解剖。 由于Mohavea的植物是四倍体（包含两个完整的基因组），因此预计它们将拥有两份CYC和两份密切相关的基因二分法（DICH）的副本。该项目将包括CYC/DICH基因家族成员的DNA测序，以提供有关该基因家族分子进化变化的信息。初步工作已经确定了四个潜在的基因产物，因此为序列分析提供了材料，以确定某些基因是否已接受更强的自然选择（如分子进化速率降低所示）。通过将对这些基因的选择性史与基因表达模式的研究结合在一起，我们将了解基因组进化过程中重复基因的命运及其在形态多样化中的作用。