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: 2114071
• 负责人: JoVonn Hill
• 金额: $ 48.73万
• 依托单位: Mississippi State University
• 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=2114071&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.

地球上所有生物多样性的存在都归功于新物种的形成。正是新形成的界限将一群个体与其他群体分开，保持了每个物种中个体的鲜明和独特的特征。新物种的形成有快有慢。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变化的原因，因为任何估计的多样化率都有多种潜在的解释。这个研究项目将集中在统计上区分这些不同的解释，以理解为什么物种多样性在不同的空间、时间和不同的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从数百个物种中每个物种的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。这些替代控制以前从未在单一研究中进行过测试。因此，这项研究将为孤立种群的形成频率和持久性（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（北美黑蝗科蚱蜢）包括跨越气候，地理和生态条件的代表，理论上影响物种形成，这将为生物多样性如何形成提供可靠的测试。通过说明在物种形成测试中种群水平取样在物种内的效用，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立一个新的基准。这样的研究对于避免误解为什么生物多样性在不同的地理区域、不同的栖息地或共存的生物群体之间存在差异是很重要的。这项研究还将强调博物馆藏品对基因组时代生物多样性研究的重要性，同时通过增加新收集和整理的标本，包括它们的DNA、生态和地理信息，增强这种可公开访问的社区资源。围绕“为什么在不同的景观或有机群体中可以促进（或抑制）多样化”这一核心研究目标，建立一个互补的公共和教育推广活动计划，将吸引不同的受众。不同分类类群的多样性差异反映了不同的多样化速度。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）：影响早期分化命运的生殖隔离的进化与影响物种形成机会的孤立种群形成和持续的频率。由于多样化研究通常是在物种谱系的系统发育估计上进行的，因此不可能检验关于物种形成机会的假设。这项研究解决了这一知识差距。通过结合理论和实证研究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测试关于多样化率（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。通过测试对多样性动态的不同控制与可能影响新物种形成的因素之间的联系（例如，破碎的栖息地，地形复杂的景观，或气候变化时期，以及物种特有的特征），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。这将是第一个建立对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化）。利用研究人员广泛的标本收集，在收集数十万个体的大规模基因组数据和最先进的分析方面取得的进展，经验数据集将包含最近（即更新世和上新世）在北美和墨西哥辐射的600多个密切相关的蚱蜢物种（其中355个来自一个属）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、基因组学和定量分析相结合，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推广活动，以接触不同的受众和服务不足的社区。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。