Dissertation Research: Molecular Data and the Evolution of Sonchus (Asteraceae: Lactuceae) in the Canary Islands

小行星9521017 海洋岛屿上动植物的多样性长期以来一直吸引着博物学家，并继续提出有关进化和地理学的挑战性问题。 研究生Seung-Chul Kim在俄亥俄州州立大学教师顾问丹尼尔Crawford教授的指导下，正在研究大西洋中部加那利群岛几个岛屿上的众多木本向日葵。 其他分类学家分析了这些植物的形态特征，他们得出结论，大约有17种Dendrosonchus栖息在加那利群岛链的各个部分。 对各种形态特征的可靠性和特定生长形式的平行进化的可能性的担忧为寻找额外的新特征以测试这些植物的当前分类学和系统发育学概念提供了理由。 这项研究将强调收集和分析所有Dendrosonchus物种和几个潜在的非洲大陆亲属的新鲜和植物标本材料的DNA序列数据，以便使用突变差异作为物种之间进化关系的衡量标准。 Macaronesian Dendrosonchus的研究将整合形态学比较，核和叶绿体基因的DNA序列差异，以及种群内和种群间遗传变异的蛋白质电泳评估。 我们的目标是构建一个强大的系统发育树的许多物种的Dendrosonchus，并检查其地理分布和形态，以了解这些植物的岛屿为基础的进化。

9521017 Crawford The diversity of plants and animals on oceanic islands has long fascinated naturalists, and continues to pose challenging questions about evolution and biogeography. Graduate student Seung-Chul Kim under the guidance of faculty adviser Prof. Daniel Crawford at Ohio State University is studying the numerous speaies of woody sunflowers of the group Dendrosonchus on the several islands of the Canaries in the mid-Atlantic Ocean. Morphological features of these plants have been analyzed by other taxonomists, who have concluded that some 17 species of Dendrosonchus inhabit various parts of the Canary Islands chain. Worries about the reliability of various morphological characters and the possibility of parallel evolution of particular growth forms provide a rationale for searching for additional, new characters to test current taxonomic and phylogenetic notions about these plants. The study will emphasize the collecting and analyzing of DNA sequence data from fresh and herbarium material of all Dendrosonchus species and of several potential mainland African relatives, in order to use mutational differences as a gauge of evolutionary relationships among the species. The study of Macaronesian Dendrosonchus will integrate morphological comparisons, DNA sequence differences in nuclear and chloroplast genes, and protein electrophoretic assessments of genetic variability within and among populations. The goal is to construct a robust phylogenetic tree for the many species of Dendrosonchus and to examine their geographical distributions and morphology in order to understand the island-based evolution of these plants.