CAREER: Seasonal migration as an ecological barrier to gene flow between hybridizing species

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。该项目将利用最先进的追踪和基因组技术，测试移民在维持和产生生物多样性方面的作用。几乎每一种动物都会迁徙，每年迁徙数千公里。迁徙路线上的相当大的变化已经被记录下来，但人们对这种变化的潜在遗传基础以及维持物种边界甚至促进新物种多样化的后果知之甚少。这项研究将利用全球无线电发射塔网络来收集斯温森画眉的迁徙路线数据，斯温森画眉是一种有东向和西向迁徙亚种的候鸟。这个物种的个体，像许多其他物种一样，每年从北美西北部的繁殖地经中美洲和南美洲迁徙到智利。本项目将评估迁徙路线的潜在遗传学，以及介于经典东西部路线之间的路线对亚种生存和维持的影响。许多广播塔是由学校主办的。因此，该项目的研究主题和基础设施也将作为美洲各地中小学和本科生教学资源的灵感来源。侧重于迁徙和进化的教育模块将为教师设计，以英语和西班牙语提供，并在画眉鸟的迁徙路线上向国际学生提供。这些模块将整合“科学的本质”教学法，突出代表性不足的群体在STEM研究中的作用，同时强调国际协调是保护迁徙物种的关键。大约30年前，人们就提出了迁徙对物种形成的重要性，但受到的关注要少得多。许多移徙者彼此相邻繁殖，但使用不同的迁徙路线。这些路线在很大程度上是由基因决定的，通常需要绕过巨大的地理障碍。因此，预计这些系统中的杂种将采取中间路线，使它们越过这些障碍，从而降低了它们的适应性和物种之间的基因流动。这个项目将测试迁移在物种形成中的作用。具体来说，最先进的鸟类追踪基础设施和基因组资源将用于(1)比较亲代和杂交画眉的存活率，(2)确定迁徙特征的遗传变异，(3)测试对杂交的选择是否对这些变异起作用。到目前为止，还没有对迁徙在物种形成中的作用进行直接测试，这给我们对物种形成的理解留下了关键的空白，因为迁徙的差异在分类学上是广泛存在的，可以帮助解释温带地区年轻物种对的优势。考虑到杂交适应性的降低源于它们的中间行为与亲代环境之间的不匹配，迁徙也可能是外在的合子后隔离屏障的一个令人信服的例子。外界隔离被认为在物种形成中是重要的，但其在自然界的程度是未知的，特别是在脊椎动物中。这项工作也将延伸到物种形成以外的领域，包括复杂行为的遗传学和保护。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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).This project will test the role of migration in maintaining and generating biodiversity using state-of-the-art tracking and genomic technology. Individuals from nearly every animal group migrate and billions of individuals, migrate thousands of kilometers each year. Considerable variation in migration route has been documented but what is less well understood is the underlying genetic basis for that variation and the consequences for maintaining species boundaries or even promoting diversification of new species. This research will make use of a global network of radio towers to collect data on migration routes in the Swainson’s thrush, a migratory bird with eastern- and western-migrating subspecies. Individuals of this species, like many others, migrate from breeding grounds in the northwestern North America via central America and south into Chile each year. This project will evaluate the underlying genetics of migration route and the consequences of routes intermediate between the classical eastern and western routes for survival and the maintenance of the subspecies. Many of the radio towers are hosted by schools. Thus, research themes and infrastructure from this project will also be used as inspiration for teaching resources for elementary, secondary, and undergraduate students across the Americas. Education modules focused on migration and evolution will be designed for teachers, provided in English and Spanish, and offered to students internationally across the migration routes of the thrush. These modules will integrate ‘nature of science’ pedagogy and highlight the role of under-represented groups in STEM research while featuring international coordination as key to the protection of migrating species. Migration’s importance for speciation was proposed nearly three decades ago but has received far less attention. Many migrants breed next to one another but use different migratory routes. These routes are largely genetically determined and often involve navigation around large geographic barriers. Accordingly, hybrids in these systems are predicted to take intermediate routes that bring them over these barriers, reducing their fitness and gene flow between species. This project will test migration’s role in speciation. Specifically, state of the art infrastructure for tracking birds and genomic resources developed to genotype hundreds of individuals at low coverage will be used to (1) compare survival rates of parental and hybrid thrushes, (2) identify genetic variants underlying migratory traits, and (3) test if selection against hybrids is acting on these variants. No direct test of migration’s role in speciation has been conducted to date, leaving critical gaps in our understanding of speciation, given that differences in migration are taxonomically widespread and could help explain the predominance of young species pairs in the temperate region. Migration could also be a compelling example of an extrinsic postzygotic isolating barrier, given that reductions in hybrid fitness derive from mismatches between their intermediate behavior and parental environments. Extrinsic isolation is thought to be important in speciation, but its extent in nature is unknown, especially in vertebrates. This work will reach fields beyond speciation as well, including the genetics of complex behavior and conservation.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.