Collaborative Research: Replicated evolution of leaf form in a neo-tropical radiation of Viburnum (Adoxaceae)

合作研究：新热带辐射中荚莲属植物（Adoxaceae）叶形的复制进化

• 批准号: 1557059
• 负责人: Michael Donoghue
• 金额: $ 59.93万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557059&HistoricalAwards=false
• 关键词: Collaborative; Research; Replicated; evolution; leaf

Much remains unknown about the genesis of biological diversity, including the origin of new species, yet such knowledge is critical to understand evolution and to make predictions about responses to rapid environmental change. This research will investigate a striking case in a group of trees and shrubs (Viburnum) in which rapid differentiation appears to have occurred repeatedly into two radically different plant forms. Major differences in the leaves of these plants appear to have resulted from adaptation to adjacent forest types that differ subtly in environmental variables. The evident replication of this process in several different mountain regions throughout the New World tropics, provides a rare opportunity to critically test a model of rapid ecological speciation. Detailed studies of adjacent plant populations will be carried out in different mountain regions in Mexico with the aim of identifying the environmental factors and the nature of the variation within populations that have favored the rapid evolution of these leaf traits. It should also be possible to identify genes that underlie these key plant characteristics by taking advantage of natural hybridization between these species. These studies will yield general insights into speciation but also into the adaptive significance of the leaf traits that differentiate related species throughout the flowering plants. This research will be carried out in collaboration with Mexican scientists and will involve multiple undergraduate and graduate students. Outreach activities have been designed to foster interactions between participants from the United States and Mexico. This project focuses specifically on understanding the drivers of speciation in three species pairs in the mountains of Eastern and Southern Mexico. The two species in each pair differ dramatically in leaf size and shape (large and round versus small and elliptical), in leaf margins (toothed versus smooth), and in leaf pubescence (densely hairy versus lacking hairs). The research will focus on quantifying variation within individual plants, within populations, and between the species pairs, and on determining the abiotic and biotic factors that differ between their forest habitats. Hypotheses on the adaptive value of the leaf variables will be tested using transects between adjacent habitats and a reciprocal transplant experiment. In areas that have long been disturbed by indigenous agricultural practices, extensive hybridization has resulted in a wide array of intermediate leaf forms. Molecular analyses of these hybrid swarms should allow the identification of the major genes that underlie differences in leaf form. This project is jointly funded with the Office of International Science and Engineering.

关于生物多样性的起源，包括新物种的起源，仍有许多未知之处，但这些知识对于理解进化和预测对快速环境变化的反应至关重要。这项研究将调查一组乔灌木(Viburnum)中的一个引人注目的案例，在这个案例中，快速分化似乎反复发生，变成两种根本不同的植物形式。这些植物叶片的主要差异似乎是由于适应了邻近的森林类型，这些森林类型在环境变量上存在细微的差异。这一过程在整个新大陆热带的几个不同山区的明显复制，为批判性地测试快速生态物种形成模型提供了难得的机会。将在墨西哥不同的山区对邻近的植物种群进行详细研究，目的是确定环境因素和种群内有利于这些叶片特征快速进化的变异的性质。还应该有可能通过利用这些物种之间的自然杂交来识别构成这些关键植物特征的基因。这些研究将产生对物种形成的一般见解，也将对在整个开花植物中区分相关物种的叶片特征的适应意义产生影响。这项研究将与墨西哥科学家合作进行，涉及多名本科生和研究生。外联活动旨在促进来自美国和墨西哥的参与者之间的互动。该项目特别侧重于了解墨西哥东部和南部山区三个物种对物种形成的驱动因素。每对中的两个种在叶大小和形状(大和圆对小和椭圆形)、叶缘(有齿对光滑)和叶短柔毛(浓密有毛与无毛)上有很大差异。这项研究将侧重于量化单个植物内部、种群内和物种对之间的差异，并确定不同森林生境之间的非生物和生物因素。关于叶片变量适应值的假设将通过相邻生境之间的横断面和相互移植实验来检验。在长期受到当地农业实践干扰的地区，广泛的杂交导致了广泛的中间叶形态。对这些杂交群体的分子分析应该能够识别导致叶片形状差异的主要基因。该项目是与国际科学与工程办公室共同资助的。