Dissertation Research: Evolution of Breeding Systems in Hawaiian Psychotria: A Phylogenetic Approach

SYTSMA 9423590这一奖项将支持对夏威夷的木霉菌及其近亲物种的研究，包括(1)分子系统发育分析和(2)不同谱系之间繁育系统变化的比较分析。由于缺乏良好的形态特征，该属的属下分类尚未得到解决，仅在区域水平上进行了处理。特别是，夏威夷成员(S)与该属其他成员的关系是有问题的。关于这一属的哈维人物种是否真的构成了一个单系群(一个自然的、相关的单位)，还是多个岛屿引入的结果，存在着相当大的争论。这项研究将确定独立引入心理疗法到夏威夷的数量。来自核核糖体ITS和叶绿体(MatK)DNA序列这两个来源的分子数据将在系统发育的背景下进行分析，以澄清这些问题。系统发展提供的信息将被用来推断岛屿内部和岛屿之间的殖民和物种形成模式。初步结果表明，在夏威夷群岛上，木霉菌的定殖和物种形成模式与先前所研究的其他生物群体的模式不一致，在这些生物群体中，最古老的岛屿包含基本的辐射元素。夏威夷精神病学提供了一个理想的模型系统，用来测试有关岛屿上植物繁殖系统的起源和维护的理论。夏威夷木兰是仅有的6个已知的双性花(雄花和雌花器官在分开的花中)产生的案例之一。将进行实地研究，在种群水平上正式确定不同物种的繁殖系统的特征，并检查夏威夷种的传粉者系统的特征。研究的一部分产生的系统发展将提供必要的历史背景，以审查不同育种系统发展的模式和过程。对这些岛屿的多次引入的潜在发生可能提供了一个独特的机会来研究复制系统中二向分化起源的选择性力量。这项研究将阐明夏威夷群岛上的一组植物之间的关系。它还将讨论与殖民生物体繁殖系统有关的重要问题，这些问题可能与涉及其他群体引进的害虫物种的问题有关。***

SYTSMA 9423590 This award will support a study of the Hawaiian species of Psychotria and their relatives, including (1) a molecular phylogenetic anaylsis and (2) comparative analysis of changes in the breeding breeding system among different lineages. Due to lack of good morphological characters, the infra-generic classification of Psychotria has not been resolved and the genus has only been treated at a regional level. In particular the relationship(s) of the Hawaiian members to the rest of the genus is in question. There is considerable debate over whether the Hawiian species of this genus really constitute a monophyletic group (a natural, related unit) or are the result of multiple introductions to the islands. This study will determine the number of independent introductions of Psychotria to Hawaii. Molecular data from two sources, nuclear ribosomal ITS and chloroplast (matK) DNA sequences will be analyzed in a phylogenetic context to clarify these issues. The information provided by the phylogeny will be used to infer patterns of colonization and speciation within and between islands. Preliminary results indiacte that patterns of colonization and speciation of Psychotria in the Hawiian islands do not confrom to previously established patterns for other groups of organisms studied in which oldest islands contain basal elements of radiations. The Hawaiian Psychotria provide an ideal model system to test theories on the origin and maintenance of plant breeding systems on islands. The Hawaiian Psychotria are one of only six known cases where dicliny (male and female organs in separate flowers) has arisen from distyly (single flowers including both male and female parts but with individual flowers having an exaggeration of the organs of one sex). Field studies will be undertaken to formally characterize the breeding systems of different species at a population level and examine characteristics of pollinator systems for the Hawaiian species of Psychotria. The phylogeny generated in one part of the study will provide the necessary historical background to examine patterns and processes in the development of different breeding systems. The potential occurrence of multiple introductions to the islands may provide a unique opportunity to examine selective forces in the origin of dicliny in replicate systems. %%% This study will clarify the relationships of a group of plants occurring in the Hawaiian islands. It will also address important questions concerning the breeding systems of colonizing organisms that may be relevant to issues involving introduced pest species in other groups. ***