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

9972612Donoghue and Ree研究生Richard Ree在哈佛大学Michael Donoghue博士的指导下，正在研究马先蒿属(玄参科)的系统发育关系和形态特征的进化模式。马先蒿是北半球的一个开花植物谱系，在中国中南部和邻近地区的山区经历了异常多样化。在这个属的许多种的相互冲突的分类分类(约.共有500个描述种)，这是由于分类学家在对物种之间的相似性进行最直观的评估时对花卉特征和营养特征的不同强调造成的。该项目的主要目的是检验这样一种假设，即马先蒿分类之间的主要差异反映了营养和花卉特征进化变化的不同速度。来自核和叶绿体DNA序列的分子数据，辅以形态数据，将被用来为该属约270个亚洲物种中的约90个样本构建一个系统发育(系谱)框架。然后将使用推断祖先状态和评估不同血统之间的异质性的方法来探索性格变化的模式和速度。该项目是首次尝试应用现代、明确的系统发育方法来研究和解释马先蒿属的花卉和营养多样性，并将为扩展分析该属和相关玄参科的其他物种提供一个框架。此外，这项研究的目标是东喜马拉雅生物多样性“热点”中物种最丰富的地区之一，因此将提供使这一偏远地区成为北温带最多样化的过程的洞察力。

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.