International Research Fellowship Program: Diversification of Amazonian Tree Lineages

国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Paul Fine博士与亚松森·卡诺博士在秘鲁利马的圣马科斯国立大学合作的为期22个月的研究奖学金。除了这一奖项外，该项目还将得到密歇根大学研究员协会的支持。该项目的标题是“亚马逊树种的多样化：环境变异对地理距离的作用”。该项目的目标是研究栖息地特有树木姐妹种群之间的进化关系，以揭示普鲁特属(草麻科)物种形成的根本原因，这是亚马逊地区树木的一个常见群体，其中包括许多土壤(土壤)专家。大多数进化生物学家认为，异地物种形成(通过空间隔离形成物种)是物种多样化的主要机制。另一种假设认为，物种通过附生物种形成(在没有空间隔离的情况下，由于当地适应环境变化而形成物种)在理论上是合理的，这一假说得到了最近的经验研究的支持，但仍未在亚马逊树木中得到检验。这是对亚马逊森林中附生物种形成的第一次直接评估。首先，正在评估土壤异质性和地理距离在四种常见亚马逊树种种群结构中的相对重要性，这些树种在白色沙土和粘土上都有亚种或变种专家。接下来，测量土壤专业化所需的性状，并量化白沙和粘土种群相邻种群之间的基因流动，以确定这些物种是否在这两种土壤类型中表现出形态差异，即使面对种群之间的基因流动。解开这些密切相关的每个分类群的系谱为研究微观和宏观进化过程的整合提供了机会--一个物种内的种群如何由于环境变化和地理距离而细分，以及这个种群中物种形成的最终原因。卡诺主任在国家植物标本馆提供了宝贵的经验，国家标本馆收藏了许多来自新热带地区的重要藏品。该项目的一个更广泛的影响是在秘鲁的国家植物标本馆试验推广新的数据库技术。该项目为世界各地的学生和教职员工提供了一个独特的机会，为未来基于标本的研究奠定基础，该研究整合了秘鲁热带植物的系统发育、生物地理学和生态学研究。总而言之，该项目有助于更好地理解导致亚马逊森林多样化的过程，并鼓励秘鲁、巴西和美国的科学家和学生之间的合作。

0402061FineThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Paul Fine to work with Dr. Asuncion Cano at the Universidad Nacional Mayor de San Marcos in Lima, Peru. This project will receive support from a University of Michigan Society of Fellows fellowship in addition to this award.The project is entitled "The diversification of Amazonian tree lineages: the role of environmental variation versus geographic distance." The goal of the project is to examine evolutionary relationships between sister populations of habitat endemic trees to reveal the ultimate causes of speciation in the genus Protium (Burseraceae), a common group of Amazonian trees which includes numerous edaphic (soil) specialists. Most evolutionary biologists believe that allopatric speciation (species formation by means of spatial isolation) is the dominant mechanism of diversification. The alternative hypothesis, that species diverge by means of parapatric speciation (species formation due to local adaptation to environmental variation in the absence of spatial isolation) is theoretically sound, has been supported by recent empirical studies, but remains untested in Amazonian trees.This is the first direct evaluation of parapatric speciation in Amazonian forests. First, the relative importance of edaphic heterogeneity and geographic distance are being evaluated in the structuring of populations of four common Amazonian tree species that have subspecific or varietal specialists on both white sand and clay soils. Next, the traits required for edaphic specialization are being measured, and the presence of gene flow between neighboring populations of white sand and clay populations quantified to see whether these species exhibit morphological divergence in the two soil types, even in the face of gene flow between populations. Unraveling the genealogy of each of these closely related taxa offers the opportunity to study the integration of micro and macro-evolutionary processes - how populations within a species become subdivided due to environmental variation and geographic distance, and the ultimate causes of speciation in this group. Director Cano is providing valuable experience in the National Herbarium, which houses many important collections from the Neotropics. One of this project's broader impacts is to pilot an extension of new databasing technology at the National Herbarium in Peru. This project represents a unique opportunity to build the foundation for future specimen-based research integrating phylogeny, biogeography, and ecological studies of tropical plants in Peru for students and faculty all over the world. In sum, this project contributes to a greater understanding of the processes that lead to diversification in Amazonian trees and is stimulating collaborations between scientists and students in Peru, Brazil, and the United States.