Dissertation Research: Phylogeny,Floral Evolution, and Patterns of Homoplasy in Pedicularis (Scrophulariaceae)

9972612Donoghue和Ree哈佛大学研究生Richard Ree在Michael Donoghue博士的指导下，正在研究马前草属（鼠尾草科）的系统发育关系和形态特征的进化模式，马前草属是北半球开花植物的一个分支，在中国中南部和邻近地区的山区经历了非凡的多样化。这一属的许多种的相互矛盾的分类分类(约…由于分类学家在对种间相似性的评价中，对花特征和营养性状的侧重点不同，导致了目前所描述的物种总数达500个。该项目的主要目的是验证一个假设，即马先蒿分类之间的主要差异反映了营养性状和花性状的不同进化速率。来自核和叶绿体DNA序列的分子数据，加上形态学数据，将用于构建该属约270个亚洲物种中约90个样本的系统发育（系谱）框架。然后，将使用推断祖先状态的方法和评估跨谱系速率的异质性来探索特征变化的模式和速率。该项目首次应用现代、明确的系统发育方法来研究和解释马先蒿属植物和营养多样性，并将为对马先蒿属和相关玄参科其他物种的扩展分析提供框架。此外，这项研究的目标是喜马拉雅东部生物多样性“热点”地区物种最丰富的地区之一，因此将为这个偏远地区成为北温带最多样化地区的过程提供见解。

9972612Donoghue and Ree Graduate student Richard Ree, under the direction of Dr. Michael Donoghue at Harvard University, is studying the phylogenetic relationships and patterns of evolution in morphological characters in the genus Pedicularis (louseworts, of family Scrophulariaceae), a northern hemisphere lineage of flowering plants that has undergone extraordinary diversification in the mountains of south-central China and neighboring regions. Conflicting taxonomic classifications of the numerous species in this genus (ca.. 500 described species in total) have resulted from differing emphases on floral features versus vegetative characters by taxonomists in their mostly intuitive assessments of similarity between species. The primary aim of the project is to test the hypothesis that major differences among classifications of Pedicularis reflect differential rates of evolutionary change in vegetative versus flower characters. Molecular data from nuclear and chloroplast DNA sequences, supplemented with morphological data, will be used to construct a phylogenetic (genealogical) framework for a sample of ca. 90 of the estimated 270 Asiatic species of the genus. Patterns and rates of character change will then be explored using methods of inferring ancestral states and assessing heterogeneity in rates across lineages. The project is the first effort to apply modern, explicit phylogenetic methods to the study and interpretation of floral and vegetative diversity in the genus Pedicularis, and it will provide a framework for extended analyses on other species in the genus and in related Scrophulariaceae. Furthermore, the research targets one of the most species-rich regions in the eastern Himalayan biodiversity "hotspot" and hence will provide insights into the processes that have made this remote region the most diverse in the northern temperate zone.