RoL: COLLABORATIVE RESEARCH: EXTREME ENVIRONMENTS, PHYSIOLOGICAL ADAPTATION, AND THE ORIGIN OF SPECIES

ROL：合作研究：极端环境、生理适应和物种起源

• 批准号: 2423844
• 负责人: Michael Tobler
• 金额: $ 78.31万
• 依托单位: University of Missouri-Saint Louis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2423844&HistoricalAwards=false
• 关键词: RoL; COLLABORATIVE; RESEARCH; EXTREME; ENVIRONMENTS

Extreme environments allow for the investigation of life's capacity and limitations to cope with far-from-average environmental conditions. Springs rich in hydrogen sulfide represent some of the most extreme freshwater environments because hydrogen sulfide halts energy production in animal cells. Nonetheless, some fish have colonized sulfide springs throughout the Americas and have evolved into new species in the process. This project will investigate how the genetic changes that mediate the fish's ability to tolerate hydrogen sulfide impact their ability to successfully interbreed with related fish that live in adjacent freshwater streams. It involves the identification of genetic differences between hydrogen sulfide-tolerant and susceptible populations, particularly in genes associated with pathways affected by hydrogen sulfide toxicity. In addition, it will be tested how hybrids between tolerant and susceptible populations differ from their parents. Specifically, the function of mitochondria and whole organisms will be compared between parents and hybrids in presence or absence of hydrogen sulfide. This project will yield new insights into how adaptation to environmental stress leads to genetic incompatibilities that represent barriers for interbreeding between populations, and thus, into how new species form. This project provides training opportunities in integrative biology for participants at all levels of higher education. It will also contribute to science education and public outreach by training scientists to become effective science communicators and reach non-expert audiences in collaboration with informal education institutions. Natural selection drives adaptive evolution and can cause speciation. However, the potential role of intrinsic genetic incompatibilities during speciation with gene flow remains largely unknown. Investigating speciation with gene flow in the context of physiological adaptation allows closing existing gaps of knowledge. This is possible through integrated analyses of how selection shapes genomic divergence, how recombination of divergent genomes in hybrids affects physiological function, and how these functional consequences affect the speciation process. This project tests a priori predictions about the links between physiological adaptation to toxic hydrogen sulfide and the emergence of reproductive isolation. It will focus on components of a highly conserved metabolic pathway, oxidative phosphorylation (OXPHOS), which plays a central role in adaptation to hydrogen sulfide. Because OXPHOS components are encoded by both the mitochondrial and the nuclear genomes, theory predicts that adaptive modification of OXPHOS should give rise to mitonuclear incompatibilities and contribute to the speciation process. This project investigates the mechanistic links between physiological adaptation and speciation by testing a priori predictions about (1) how OXPHOS adaptation affects genomic divergence between populations living in different environments, (2) the functional consequences of mitonuclear incompatibilities at the biochemical, physiological, and organismal levels, and (3) the relative role of mitonuclear incompatibilities during speciation. The project employs an integrative approach that combines population genomics, assays of enzyme, organelle, and whole organism function, as well as field and laboratory experiments for the quantification of multiple pre- and postzygotic mechanisms of reproductive isolation.This award was co-funded by BIO/Emerging Frontiers, DEB/Evolutionary Processes, and IOS/Integrative Ecological Physiology.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.

极端环境允许调查生命应对远离平均水平的环境条件的能力和局限性。富含硫化氢的泉水代表了一些最极端的淡水环境，因为硫化氢会阻止动物细胞产生能量。尽管如此，一些鱼已经在整个美洲的硫化物泉水中定居，并在这个过程中进化成了新的物种。该项目将调查调节鱼类耐受硫化氢能力的基因变化如何影响它们成功地与生活在邻近淡水溪流中的相关鱼类杂交的能力。它涉及识别耐硫化氢和敏感种群之间的遗传差异，特别是与受硫化氢毒性影响的途径相关的基因差异。此外，还将测试耐受群体和敏感群体之间的杂交与其亲本有何不同。具体地说，线粒体和整个生物体的功能将在有或没有硫化氢的情况下在双亲和杂交种之间进行比较。该项目将对适应环境压力如何导致遗传不亲和性产生新的见解，这些不亲和性是种群间杂交的障碍，从而也将对新物种的形成产生新的见解。该项目为各级高等教育的参与者提供了综合生物学的培训机会。它还将通过培训科学家成为有效的科学传播者，并与非正规教育机构合作接触非专家受众，从而促进科学教育和公众宣传。自然选择推动适应性进化，并可能导致物种形成。然而，固有的遗传不亲和性在物种形成和基因流动过程中的潜在作用在很大程度上仍不清楚。在生理适应的背景下用基因流研究物种形成，可以弥合现有的知识差距。这可以通过综合分析选择如何形成基因组分歧，杂交后代中不同基因组的重组如何影响生理功能，以及这些功能后果如何影响物种形成过程来实现。这个项目测试了对有毒硫化氢的生理适应与生殖隔离的出现之间的联系的先验预测。它将专注于高度保守的代谢途径的组成部分，氧化磷酸化(OXPHOS)，它在适应硫化氢的过程中发挥核心作用。由于OXPHOS组分同时由线粒体和核基因组编码，理论预测OXPHOS的适应性修饰应该会导致有丝分裂不亲和性，并有助于物种形成过程。本项目通过检验以下先验预测来研究生理适应和物种形成之间的机制联系：(1)OXPHOS适应如何影响生活在不同环境中的种群之间的基因组差异，(2)在生化、生理和生物水平上有丝分裂不亲和性的功能后果，以及(3)有丝分裂不相容在物种形成过程中的相对作用。该项目采用了一种综合的方法，结合了种群基因组学、酶、细胞器和整个生物体的功能分析，以及用于量化生殖隔离的多种合子前和合子后机制的野外和实验室实验。该奖项由BIO/Emerging Frontiers、DEB/进化过程和IOS/综合生态生理学共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。