Evolutionary and neurogenomic mechanisms of species discrimination during character displacement

物种形成是新物种形成的基本进化过程。行为隔离通常在物种形成中起着关键作用，当交配特征（信号和/或对这些信号的歧视）不匹配阻止密切相关的物种进行杂交时，就会发生行为隔离。信号变化与信号歧视变化对行为隔离的相对重要性仍然未知，因为研究诸如歧视等认知特征传统上对自然种群构成了重大挑战。现在在非模型系统中开发基因组资源和功能遗传工具是可行的，这为研究行为隔离的神经和遗传基础提供了一个令人兴奋的机会。该项目将整合尖端的转录组学和基因组学方法，将物种内的行为、神经和基因组变异模式与物种多样化的大规模过程联系起来。这项创新的工作将通过确定选择如何作用于行为隔离背后的认知特征，为产生和维持生物多样性的机制提供新的见解，从而推动该领域的发展。该项目的更广泛影响集中在发展旨在支持生物学中代表性不足的群体的倡议。第一，为少数民族服务学校的中等教育教师提供以探究性学习为中心的培训机会和课程资源。第二，将通过一个现有的当地项目为有兴趣获得编程经验的女孩设计和实施生物学编程课程。第三，来自代表性不足群体的学生将被招募到这个项目的有偿研究职位。种间生殖相互作用在物种多样化中起着关键作用，它有利于近亲物种之间的同域性相对于异域性的增强行为隔离的进化，从而导致特征位移的模式。理解行为隔离背后的特征是如何进化的，对于理解物种是如何以这种方式多样化的至关重要。然而，人们对行为隔离的近似机制知之甚少，这代表了我们对物种形成的理解中的一个关键空白。该项目将验证一种假设，即物种歧视背后的认知特征选择在行为隔离的进化中起着关键作用。在该系统中，将结合最近开发的基因组资源和功能工具，充分记录了北美流鱼类多样化群体鲷鱼的特征位移模式。共感神经系统中增强行为隔离的机制基础将通过三种方法进行研究：(1)将在实验室中培养同域和异域种群的个体，研究遗传和环境对物种歧视的影响；(2)行为相关神经元的分子谱分析将揭示物种歧视的神经基因组基础；(3)同域和异域种群的种群基因组分析将确定行为隔离和物种形成的遗传基础。这个综合项目将为行为隔离的机制基础提供前所未有的见解。此外，该项目将支持开发教育、培训和指导资源，面向STEM中代表性不足群体的中学生和大学生，以及来自少数族裔学校的高中生物教师。本项目由综合与有机系统学部的行为系统集群和环境生物学学部的进化过程项目共同资助。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。

Speciation is a fundamental evolutionary process by which new species form. Behavioral isolation often plays a key role in speciation and occurs when mismatches in mating traits (signals and/or discrimination of those signals) prevent closely related species from interbreeding. The relative importance of changes in signals versus changes in signal discrimination to behavioral isolation remains unknown, as studying cognitive traits such as discrimination has traditionally posed a major challenge in natural populations. It is now feasible to develop genomic resources and functional genetic tools in non-model systems, providing an exciting opportunity to investigate the neural and genetic basis of behavioral isolation. This project will integrate cutting-edge transcriptomic and genomic approaches to connect patterns of behavioral, neural, and genomic variation within species to large-scale processes of species diversification. This innovative work will move the field forward by identifying how selection acts on cognitive traits underlying behavioral isolation, providing novel insight into the mechanisms that generate and maintain biodiversity. The broader impacts of this project focus on developing initiatives aimed at supporting underrepresented groups in biology. First, training opportunities and curriculum resources centered on inquiry-based learning will be provided to secondary education teachers from minority serving schools. Second, curriculum on coding for biology will be designed and implemented through an existing local program for girls interested in gaining experience in coding. Third, students from underrepresented groups will be recruited for paid research positions on this project. Interspecific reproductive interactions can play a key role in species diversification by favoring the evolution of enhanced behavioral isolation in sympatry relative to allopatry between closely related species, resulting in a pattern of character displacement. Understanding how traits underlying behavioral isolation evolve is central to understanding how species diversify in this manner. Yet, strikingly little is known about the proximate mechanisms of behavioral isolation, representing a critical gap in our understanding of speciation. This project will test the hypothesis that selection on cognitive traits underlying species discrimination plays a key role in the evolution of behavioral isolation. Well-documented patterns of character displacement in darters, a diverse group of North American stream fishes, will be leveraged in combination with recently developed genomic resources and functional tools in this system. The mechanistic basis of enhanced behavioral isolation in sympatry will be investigated using three approaches: (1) individuals from sympatric and allopatric populations will be raised in the lab to investigate the genetic and environmental contributions to species discrimination, (2) molecular profiling of behaviorally relevant neurons will uncover the neurogenomic basis of species discrimination, and (3) population genomic analyses in sympatric and allopatric populations will identify the genetic basis of behavioral isolation and speciation. This integrative project will provide unprecedented insight into the mechanistic basis of behavioral isolation. Furthermore, this project will support the development of educational, training, and mentorship resources for secondary and post-secondary students from groups underrepresented in STEM and for high school biology teachers from minority-serving schools.This project is jointly funded by the Behavioral Systems Cluster in the Division of Integrative and Organismal Systems, and the Evolutionary Processes program in the Division of Environmental Biology.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.