Dissertation Research: Systematics, biogeography and taxonomy of the pantropical legume genus Cynometra

豆科植物是开花植物的第三大家族。这些具有经济和生态意义的植物大小不等，从微小的沙漠草本植物到巨大的雨林树木。虽然最近的研究已经阐明了家庭中主要谱系之间的关系，但对近20，000个物种中的许多物种知之甚少，特别是产生这种多样性的过程。这项研究将使用最近开发的“下一代”DNA测序方法和统计计算机建模，以解决一个大的和广泛的热带豆科植物群之间的进化关系，并推断什么样的作用，如果有的话，适应新的环境中发挥了这些物种的多样化。 鉴于它们的广泛分布和生态多样性，了解这些物种之间的关系将为未来的比较研究提供一个框架，并提高我们对豆科植物的整体进化的理解。本研究将结合联合收割机基因组学、生态位建模和化石记录的信息，阐明热带Cynometra属和Maniltoa属物种之间的关系，并探讨生态位保守性在植物地理学和物种形成机制中的作用。下一代测序正在彻底改变分类学、地理学和进化生物学的实践。虽然这项技术已经应用于非常深和非常浅的进化问题，但它在物种水平的遗传学，特别是植物中的应用仍然有限。然而，正是在物种层面上，这些新技术最有希望解决以前棘手的关系。此外，当结合生态位建模和地理范围的数据，以及解决这些方法能够产生的物种形成机制和生态位保守性在产生观察到的多样性模式的作用，让研究人员。例如，如果异域姊妹种始终沿着环境轴沿着，那么生态介导的选择可能在物种形成中起作用，而如果异域姊妹种在非生物生态位空间中始终相同或几乎相同，那么生态分歧不是驱动物种形成的主要因素。 为了解决这个问题，研究人员将：1）进行实地工作并参观巴西的植物标本馆（该属的多样性中心）以更好地表征巴西物种的多样性和分布; 2）使用靶向序列捕获技术产生的数据重建良好分辨的物种水平的亲缘关系;（3）利用生态位模型和分布数据，对组成物种的非生物生态位进行表征。这些数据的分析将提供一个更精确的理解Cynometra和Maniltoa的进化和地理历史和驱动这些过程的机制。

Legumes are the third largest family of flowering plants. These economically and ecologically significant plants range in size from tiny desert herbs to giant rainforest trees. While recent research has elucidated relationships among the major lineages in the family, little is known about many of the nearly 20,000 species, especially the processes that generate this diversity. This study will use recently developed 'next generation' DNA sequencing methods and statistical computer modeling to resolve the evolutionary relationships among a large and widespread group of tropical legumes and to infer what role, if any, adaptation to new environments has played in the diversification of these species. Given their wide distribution and ecological diversity, understanding the relationships among these species will provide a framework for future comparative studies and enhance our understanding of the overall evolution of the legume family. The project will also include a significant training component to expose undergraduates in STEM fields to the latest tools and analytic methods.This study will combine phylogenomics, ecological niche modeling, and information from the fossil record to elucidate the relationships among the species of the tropical genera Cynometra and Maniltoa and will investigate the role niche conservatism plays in biogeography and speciation mechanisms. Next generation sequencing is revolutionizing the practice of systematics, biogeography, and evolutionary biology. While the technology has been applied to both very deep and very shallow evolutionary questions, its application to species level phylogenetics, particularly in plants, remains limited. However, it is at the species level that these new techniques hold the greatest promise to resolve previously intractable relationships. In addition, when combined with ecological niche modeling and geographic range data, the well resolved phylogenies these methods are capable of producing allow researchers to study speciation mechanisms and the role of niche conservatism in generating observed patterns of diversity. If, for example, allopatric sister species consistently segregate along environmental axes, then ecologically mediated selection may have a role in speciation, whereas if allopatric sister species are consistently identical or nearly identical in abiotic niche space, then ecological divergence is not a major factor driving speciation. To address this question, the researchers will: 1) conduct field work and visit herbaria in Brazil (the center of diversity for the genus) to better characterize diversity and distributions of Brazilian species; 2) reconstruct a well resolved species level phylogeny using data generated with targeted sequence capture techniques; and 3) characterize the abiotic niche of the constituent species using ecological niche modeling and distribution data. Analyses of these data will provide a much more precise understanding of evolutionary and biogeographic history of Cynometra and Maniltoa and the mechanisms driving these processes.