Collaborative Research: Testing Hypotheses about Rates of Diversification & Controls on Diversification related to the Opportunities for Speciation vs Fate of Incipient Diverge

合作研究：检验有关多元化率的假设

• 批准号: 2114070
• 负责人: L. Lacey Knowles
• 金额: $ 81.15万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114070&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Hypotheses; about

All of combined planetary biodiversity owes its existence to the formation of new species. It is the newly formed boundaries separating one group of individuals from others that maintain the distinct and unique characteristics of individuals in each species. New species can form quickly or slowly. Depending upon this pace of species formation (i.e., the rate of diversification), the numbers of species within a group will differ. However, the diversification rate itself is not sufficient to understand why species diversity varies because there are multiple potential explanations for any estimated diversification rate. This research project will focus on statistically distinguishing among these different explanations in order to understand why species diversity differs across space, time, and among different groups of organisms. Specifically, by applying newly developed statistical models of species formation to genomic sequences from individuals collected across multiple populations within each of several hundred species, the research will distinguish between various potential controls on diversification. These alternative controls have never previously been tested within a single study. As such, the research will provide unprecedented insights into how the frequency of formation and persistence of isolated populations (and hence, the opportunities for new species to form) affects diversification rates. The targeted study group (North American Melanoplinae grasshoppers) includes representatives that span the climatic, geographic, and ecological conditions theorized to affect species formation, which will provide robust tests of how biodiversity is shaped. By illustrating the utility of population-level sampling within species in tests of species formation, the project will set a new benchmark for other researchers to consider for their own biodiversity studies. Such research is important to avoid misinterpretations about why biodiversity differs across geographic regions, or among habitats, or among groups of organisms that co-occur. The research will also highlight the importance of museum collections for genomic-era biodiversity studies, while enhancing this publicly accessible community resource through the addition of newly collected and curated specimens, including their DNA, ecological and geographic information. A complementary program of public and educational outreach activities built around the core research objective of why diversification might be promoted (or inhibited) across different landscapes or organismal groups will reach a diverse audience.Diversity differences observed across taxonomic groups reflect different rates of diversification. However, there are two fundamentally different controls on diversification dynamics (meaning there are different explanations for any given diversification rate): the evolution of reproductive isolation that affects the fate of incipient divergences versus the frequency with which isolated populations form and persist affecting the opportunities for speciation. Because diversification studies are typically carried out on phylogenetic estimates of species lineages, it has not been possible to test hypotheses about the opportunities for speciation. This research addresses this knowledge gap. Through combined theoretical and empirical studies and the generation of large-scale genomic data, the research will apply newly developed analytical methods to test hypotheses about diversification rates (based on phylogenetic estimates of species lineages) vs. the controls on diversification dynamics (based on phylogenetic estimates of species and population lineages). By testing for linkages between different controls on diversification dynamics with factors potentially affecting the formation of new species (e.g., fragmented habitats, topographically complex landscapes, or periods of climatic change, and species-specific traits), the work will address why these conditions might promote or inhibit the formation of new species. This will be the first study to establish potential linkages between the various controls on diversity dynamics (e.g., topographic complexity, geologic and climatic events, and selectively driven divergence). Leveraging the researchers’ extensive specimen collections with advances in collecting large-scale genomic data across hundreds of thousands of individuals and state-of-the-art analytics, the empirical dataset will contain almost complete taxonomic coverage of over 600 closely related grasshopper species (355 of which are from a single genus) that radiated recently (i.e., within the Pleistocene and Pliocene) in North America and Mexico. By combining the skillsets of researchers with taxonomic expertise and genomic and quantitative analytics, the research team will promote broad training and mentoring of graduate students, while also offering public and educational outreach activities developed by researchers with different backgrounds to reach diverse audiences and underserved communities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

所有联合行星生物多样性的存在都归功于新物种的形成。正是新形成的边界将一组个体与其他个体分开，保持了每个物种中个体的独特特征。新物种可以快速或缓慢地形成。根据物种形成的速度（即多样化的速度），一个群体内的物种数量会有所不同。然而，多样化率本身不足以理解物种多样性为何变化，因为任何估计的多样化率都有多种潜在的解释。该研究项目将侧重于在统计上区分这些不同的解释，以了解为什么物种多样性在空间、时间和不同生物群体之间存在差异。具体来说，通过将新开发的物种形成统计模型应用于数百个物种中多个种群中收集的个体的基因组序列，该研究将区分对多样化的各种潜在控制。这些替代对照以前从未在单一研究中进行过测试。因此，该研究将为孤立种群的形成和持续存在频率（以及新物种形成的机会）如何影响多样化率提供前所未有的见解。目标研究小组（北美黑蚱蜢）包括跨越理论上影响物种形成的气候、地理和生态条件的代表，这将为生物多样性如何形成提供强有力的测试。通过说明物种内种群水平抽样在物种形成测试中的效用，该项目将为其他研究人员在他们自己的生物多样性研究中考虑设定新的基准。此类研究对于避免误解生物多样性为何在不同地理区域、不同栖息地或不同共生生物群体之间存在差异非常重要。该研究还将强调博物馆藏品对于基因组时代生物多样性研究的重要性，同时通过添加新收集和整理的标本（包括其 DNA、生态和地理信息）来增强这一可公开访问的社区资源。围绕为什么不同景观或生物群体的多样化可能被促进（或抑制）的核心研究目标而建立的公共和教育推广活动的补充计划将覆盖不同的受众。在分类群体之间观察到的多样性差异反映了不同的多样化率。然而，对多样化动态有两种根本不同的控制（意味着对任何给定的多样化率都有不同的解释）：影响初期分化命运的生殖隔离的进化与影响物种形成机会的隔离种群形成和持续的频率。由于多样化研究通常是对物种谱系的系统发育估计进行的，因此不可能检验有关物种形成机会的假设。这项研究解决了这一知识差距。通过理论和实证研究相结合以及大规模基因组数据的生成，该研究将应用新开发的分析方法来检验关于多样化率（基于物种谱系的系统发育估计）与多样化动态控制（基于物种和种群谱系的系统发育估计）的假设。通过测试对多样化动态的不同控制与可能影响新物种形成的因素（例如，分散的栖息地、复杂的地形景观或气候变化时期以及物种特定特征）之间的联系，这项工作将解决为什么这些条件可能促进或抑制新物种的形成。这将是第一项建立多样性动态的各种控制之间潜在联系的研究（例如地形复杂性、地质和气候事件以及选择性驱动的分歧）。利用研究人员广泛的标本收藏以及收集数十万个体的大规模基因组数据和最先进的分析技术，经验数据集将包含最近在北美和墨西哥辐射的 600 多个密切相关的蝗虫物种（其中 355 个来自单一属）的几乎完整的分类覆盖。通过将研究人员的技能与分类学专业知识以及基因组和定量分析相结合，研究团队将促进对研究生的广泛培训和指导，同时还提供由不同背景的研究人员开发的公共和教育外展活动，以接触不同的受众和服务不足的社区。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持 标准。