Dissertation Research: Patterning of Morphological Diversification: Evolution of Floral Form in Tribe Amorpheae (Fabaceae)

9902206 Hufford和McMahon了解有机体类群之间的形态多样性模式是系统学的一个关键方面。在豆类亚科的12,000种植物中，豌豆状的花是高度保守的；但在新大陆部落紫穗花族(包括达雷亚属的“草原三叶草”)，花的形状和发育都高度改变，往往不像豌豆。为了了解紫穗花亚科植物多样性的历史起源，研究生米歇尔·麦克马洪将在华盛顿州立大学拉里·赫福德博士的指导下，分析该部落物种之间的历史关系(代表性类群的谱系或系统发育)，重点是叶绿体matK基因的DNA测序作为主要证据来源。此外，将对花型进行全面的形态计量学研究，以准确评估花瓣和雄蕊的结构相似性，并建立分类群之间变异的全面范围和分布。将采取两种方法来综合花型的系统发育和多样性。首先，在分子系统发育框架下分析的结构相似(同源)花部分的发育数据，可以提供关于不同成体起源所涉及的进化转化的见解。其次，可以将映射到系统发育上的关键花器官的详细测量数据与花特征进化变化的零模型进行比较，以确定特征组合或趋势的独特和重复的模式。系统发育和发育数据的综合应该有助于解释紫穗菊科植物的花型模式，这种模式可能是由于成虫和早期特征之间的相关性、进化速度的加快或通过新的反复出现的特征组合而进化的。这项拟议的工作将为深入分析花的形态进化和理解紫穗菊属不同谱系之间的多样性模式是如何发生的提供技术。

9902206Hufford and McMahon Understanding patterns of morphological diversity among groups of organismsis a key aspect of systematics. Among the 12,000 species of the legume subfamily Papilionoideae, pea-like flowers are highly conserved; but in the New World tribe Amorpheae (including "prairie clovers" of the genus Dalea) flower forms are highly modified, and often not pea-like in shape or development. To understand the historical origins of this floral diversity in Amorpheae, graduate student Michelle McMahon, under the direction of adviser Dr. Larry Hufford at Washington State University, will be analyzing the historical relationships (the genealogy or phylogeny of representative taxa) among species in the tribe with emphasis on DNA sequencing of the chloroplast matK gene as main source of evidence. In addition, a thorough morphometric study will be made of floral forms to assess accurately structural similarities in petals and stamens and to establish the full range and distribution of variation among taxa. Two approaches will be taken to synthesize phylogeny and diversity of floral form. First, developmental data for structurally similar (homologous) flower parts, analyzed in the context of the molecular-phylogenetic framework, can provide insights about the evolutionary transformations involved in the origin of disparate adult forms. Second, detailed measurement data of key floral organs mapped onto a phylogeny can be compared with null models of evolutionary change in floral characters, in order to determine unique as well as recurring patterns of character combinations or trends. A synthesis of phylogenetic and developmental data should help to explain patterns of floral form in Amorpheae, patterns that may be due to correlations between adult and early-stage characters, to accelerated rates of evolution, or to evolution through new combinations of recurring features. The proposed work will provide techniques for the thorough analysis of floral form evolution and an understanding of how patterning of diversity among lineages has occurred in Amorpheae.