DISSERTATION RESEARCH: Phylogeny and Biogeography of Euphorbiaceae Tribe Crotoneae

这项研究将使用基于DNA序列的系统发育分析和分子弧校准来重建巴豆族(大戟科)的系统发育和生物地理。这个类群中最大的属是巴豆属，全世界有1200到1300种，以前的非分子研究将其归类于东半球大戟科的一个类群。最近的分子研究表明，在重新定义的巴豆亚族中，巴豆与八个小得多的新大陆属结盟。除了南美洲的一小段外，巴豆仍然是单系的，东半球的成员都嵌入了该属的新大陆谱系中。巴豆亚科的剩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。许多鳄鱼是稀有的，因此受到保护的关注。我们的研究将集中在加勒比地区以及克罗顿和它的近亲是如何在新大陆进化的。该项目的更广泛的影响包括培训合作者(博士生)，积极与美国、墨西哥、古巴和巴西的研究人员合作，本科生参与研究，增强加勒比生物地理学中植物群的知识，以及研究一个巨大而复杂的属的进化。

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.