Dissertation Research: Molecular Systematics and Evolution in Mimulus and Tribe Mimuleae

系统学家肩负着量化和描述大群生物多样性的艰巨任务，以及识别与物种划定相对应的形态或遗传多样性中的不连续之处。这些任务对于拥有1)已成为研究进化和生态学的模式系统的物种，以及2)大量稀有或受威胁物种的群体来说尤其关键。植物Mimulus属的物种已经成为研究自然界进化过程的模式系统，因为该属的有趣的特征和适应的多样性。这种世界范围内的物种具有不同的染色体数量、繁殖策略和传粉者，以及对极端环境的有趣适应。Mimulus的许多物种也是稀有的。对分布广泛、物种丰富的种群的系统发育估计很重要，因为它们为生物学家提供了研究大范围多样化事件的机会，在这些事件中，可能发生了平行辐射进入空间分离的相似环境的事件。对物种间进化关系的估计有助于记录这些辐射并进行比较分析。系统学家在界定物种方面的作用同样至关重要。保护计划和进化过程的研究需要对物种进行准确的界定。该项目的目的是：1)确定Mimulus与其他属的关系，2)确定Mimulus是否是一个自然类群，3)估计Mimulus内物种水平的关系并确定分类单位，4)探索Mimulus在澳大利亚新发现的辐射的进化模式。拟议的研究将实现两个目标。我们将使用来自两个不同基因组的DNA序列信息来进一步发展新发现的澳大利亚Mimulus分支的物种水平的系统发育假说。这些分析将为新划定的金莲科植物的多样性提供一个合适的全球视角。这也将为评估这一组的形态变化提供一个明确的系统发育框架，并将作为未来比较研究的基础。我们将利用DNA序列和多态DNA片段来分析含羞草组的遗传多样性。尤纳努斯。这些模式将被用来指导分类单元的划分，并将作为一个模式来定义形态特征差异很小的组中的分类单元。由于它的许多物种都是稀有物种，准确的物种划分对于制定适当的管理政策至关重要。

Systematists are charged with the difficult tasks of quantifying and characterizing diversity in large groups of organisms and of identifying discontinuities in morphological or genetic diversity that correspond with species delimitations. These tasks are especially critical for groups that have, 1) species that have become model systems for studying evolution and ecology, and 2) a large number of rare or threatened species. Species in the plant genus Mimulus have become model systems for the study of evolutionary processes in nature due to the diversity of interesting traits and adaptations in the genus. Species in this worldwide genus have different chromosome numbers, reproductive strategies, and pollinators, and interesting adaptations to extreme environments. Many species of Mimulus are also rare. Phylogenetic estimates of widely distributed, species-rich groups are important, because they give biologists the opportunity to study broad-scale diversification events, in which parallel radiations into spatially separated, similar environments may have occurred. An estimate of the evolutionary relationships among the species is useful in documenting these radiations and enables comparative analyses. The role of systematists in delimiting species is equally vital. Conservation plans and studies of evolutionary processes require accurate circumscription of species. The purposes of this project are: 1) to determine the relationship of Mimulus to other genera, 2) to determine whether Mimulus is a natural group, 3) to estimate species-level relationships and define taxonomic units within Mimulus and 4) to explore evolutionary patterns in the newly recognized radiation of Mimulus in Australia. The proposed research will accomplish two goals. We will use DNA sequence information from two different genomes to further develop species-level phylogenetic hypotheses in the newly recognized Australian Mimulus clade. These analyses will provide an appropriate global perspective on diversification in the newly circumscribed family Phrymaceae. These will also provide an explicit phylogenetic framework for evaluating morphological changes in this group and will serve as a basis for future comparative studies. We will use DNA sequence and polymorphic DNA fragments to analyze patterns of genetic diversification in Mimulus sect. Eunanus. These patterns will be used to guide taxon delimitation and will serve as a model for defining taxa in groups with few morphological character differences. Because many of its species are rare, accurate species delimitation in Mimulus is critical to establishing appropriate management policies.