DISSERTATION RESEARCH: Phylogeny and Biogeography of Euphorbiaceae Tribe Crotoneae

本研究将利用基于DNA序列的系统发育分析和分子钟校准来重建巴豆族（大戟科）的系统发育和系统地理。这一组中最大的属是巴豆属，全世界有1,200到1,300个物种，以前的非分子研究将其与旧大陆的大戟科的一组姐妹。最近的分子学研究表明，巴豆与新大陆的8个小得多的属在一个重新定义的巴豆族中有亲缘关系。除了一个南美的小部分外，巴豆属仍然是单系的，旧大陆的成员被嵌入到该属的新大陆谱系中。巴豆科的其余属中有一半是加勒比海盆地特有的，另一半是南美洲特有的。许多Crotoneaetaxa是罕见的，因此保护的关注。我们的研究将集中在加勒比地区，以及巴豆和它的近亲如何在新世界进化。学生），与美国的研究人员积极合作，墨西哥，古巴和巴西，参与研究的本科生，提高植物群体在加勒比海植物地理学的知识，并对一个巨大的，复杂的属的进化研究。

This study will use DNA sequence-based phylogenetic analyses and molecularclock calibrations to reconstruct the phylogeny and biogeography of the Crotoneae tribe(Euphorbiaceae). The largest genus in this group is Croton, with 1,200 to 1,300 speciesworldwide, which previous nonmolecular studies placed sister to an Old World group ofEuphorbiaceae. Recent molecular work shows instead that Croton is allied to eight muchsmaller New World genera in a redefined Crotoneae tribe. Croton remains monophyleticexcept for one small South American section, and the Old World members are embeddedwithin New World lineages of the genus. Half of the remaining genera of Crotoneae areendemic to the Caribbean basin and the other half are South American. Many Crotoneaetaxa are rare and therefore of conservation concern. Our study will focus on theCaribbean region and how Croton and its closest relatives evolved in the New World.The broader impacts of the project include training of the co-PI (Ph.D. student),active collaboration with investigators in the U.S., Mexico, Cuba, and Brazil,participation of undergraduates in the research, enhancing knowledge of plant groups inCaribbean biogeography, and research on the evolution of a giant, complex genus.