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

SYTSMA 9423590 该奖项将支持对夏威夷九节属物种及其亲属的研究，包括（1）分子系统发育分析和（2）不同谱系之间育种系统变化的比较分析。 由于缺乏良好的形态特征，九节属的属下分类尚未解决，该属仅在区域水平上进行了处理。 特别是夏威夷成员与该属其他成员的关系受到质疑。有相当多的争论是否夏威夷物种的这个属真的构成一个单系群（一个自然的，相关的单位）或多个引进到岛上的结果。 这项研究将确定独立引进九节到夏威夷的数量。 从两个来源，核核糖体ITS和叶绿体（matK）DNA序列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。 生物发生学提供的信息将用于推断岛屿内部和岛屿之间的殖民化和物种形成模式。 初步结果indiacte的殖民化和形态的九节在夏威夷群岛的模式不confrom以前建立的模式，其他群体的生物体研究，其中最古老的岛屿含有基本元素的辐射。 夏威夷九节提供了一个理想的模式系统，以测试理论的起源和维持植物育种系统的岛屿。 夏威夷九节花是已知的仅有的六种雌雄异株（不同花中的雄性和雌性器官）起源于异株（单花包括雄性和雌性部分，但个别花具有一种性别的器官）的案例之一。 将进行实地研究，以正式确定不同物种在种群水平上的繁殖系统的特征，并研究夏威夷九节属物种的传粉系统的特征。 在研究的一部分中产生的遗传学将提供必要的历史背景，以研究不同育种系统发展的模式和过程。 潜在的发生多个引进的岛屿可能提供一个独特的机会，检查选择性的力量在复制系统中的雌雄异株的起源。 这项研究将澄清一组植物发生在夏威夷群岛的关系。 它还将讨论有关定殖生物繁殖系统的重要问题，这些问题可能与其他群体中引入的有害生物物种的问题有关。 ***

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. ***