Phylogenetics and Biogeography of Subtribe Butiinae (Cocoeae, Palmae)

0212779哈恩和诺布里克博士。哥伦比亚大学的威廉·哈恩和蒙哥马利植物中心的拉里·诺布里克博士正在结合他们的分子和形态专业知识，研究椰子及其近缘分类的系统学和进化。椰子是经济上最重要的三种棕榈树之一，但人们对它的起源和关系知之甚少。棕榈族Cocoeae由22个属组成(包括椰子)，其中马达加斯加有两个属，南非有一个属，东南亚和太平洋有一个属，其余18个属在新大陆。由于在过去的几十年里已经提出了几种不同的分类，因此需要对该部落的现有分类进行关键的重新评估。需要对进化关系的估计来解决这些分类学上的争论，以及关于椰子地理起源的争论。该物种似乎原产于东南亚和南太平洋，但它的所有近亲都在非洲、马达加斯加或新大陆发现。由于其显著的漂浮扩散能力，人们提出了自然扩散和人为扩散两种方式来解释其来源和洋流分布。提出了两种主要的地理设想：从马达加斯加/非洲横跨印度洋，或从美洲横跨太平洋。为了在这些相互竞争的生物地理学假说之间做出选择，有必要对椰子与其他棕榈树的关系进行明确的研究。哈恩和诺布利克斯博士的研究使用现代分子和形态系统学方法重建了椰子及其近缘物种的进化史，并开发了一个用于评估多样性速度的分子时钟框架。将积累形态和分子数据，以评估组成Cocoeae部落的22个属之间的进化关系，并预期在属水平上的界限和分类方面的改进。分子时钟(基于多个核和叶绿体基因)将被用来确定该部落各分类群之间的分化事件的日期，并估计椰子的起源时间。基于这些结果，可以对可供选择的分类学和生物地理假说进行测试，从而更好地理解经济上重要的作物物种的进化过程。研究生和本科生都将在这个项目中得到支持，并将在田野、植物园、植物标本馆、计算机和分子进化技术方面得到指导。这些研究的结果也将在佛罗里达州迈阿密的蒙哥马利植物中心的公共教育项目中公布。

0212779Hahn and NoblickDr. William Hahn of Columbia University and Dr. Larry Noblick of the Montgomery Botanical Center are combining their molecular and morphological expertise to study the systematics and evolution of the coconut, Cocos nucifera, and its taxonomic relatives. The coconut is one of the three most economically important species of palms, yet its origins and relationships are poorly understood. The palm tribe Cocoeae consists of 22 genera (including the coconut) with two genera in Madagascar, one genus in South Africa, the coconut in Southeast Asia and the Pacific, and the remaining 18 genera in the New World. Available taxonomies for the tribe are in need of critical reevaluation as several different taxonomies have been proposed over the past few decades. An estimate of evolutionary relationships is needed to resolve these taxonomic debates as well as controversy over the geographic origin of the coconut. The species appears to be native to Southeast Asia and the South Pacific, but all of its close relatives are found in Africa, Madagascar, or the New World. Because of its remarkable ability to disperse by floating, both natural and human-mediated dispersal have been suggested to explain its origins and current distribution. Two primary geographic scenarios have been proposed: from Madagascar/Africa across the Indian Ocean or from the Americas across the Pacific Ocean. An explicit examination of the coconut's relationships to other palms is necessary to choose between these competing biogeographic hypotheses.Dr. Hahn and Dr. Noblicks's research uses modern molecular and morphological phylogenetic methods to reconstruct the evolutionary history of the coconut and related species and to develop a molecular clock framework for the evaluation of rates of diversification. Morphological and molecular data will be accumulated to estimate evolutionary relationships among the 22 genera that form tribe Cocoeae, with anticipated improvements to genus-level circumscription and classification. Molecular clocks (based on multiple nuclear and plastid genes) will be used to date divergence events among the taxa in this tribe and to estimate the time of origin for the coconut. Based on these results, tests of alternative taxonomic and biogeographic hypotheses can be conducted, leading to a better understanding of the evolutionary process in an economically important crop species. Both graduate and undergraduate students will be supported in this project and will be instructed in field, botanical garden, herbarium, computer, and molecular evolutionary techniques. Results of these studies will also be presented in the public education programs of the Montgomery Botanical Center in Miami, Florida.