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。该项目将使用最先进的跟踪和基因组技术测试移民在维护和产生生物多样性方面的作用。几乎每一个动物群体的个体都会迁徙，每年有数十亿的个体迁徙数千公里。迁徙路线的相当大的变化已被记录在案，但不太清楚的是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。这项研究将利用全球无线电发射塔网络收集关于斯温森画眉迁徙路线的数据，斯温森画眉是一种有东部和西部迁徙亚种的候鸟。像许多其他物种一样，这个物种的个体每年从北美洲西北部的繁殖地经中美洲向南迁移到智利。该项目将评估迁移路线的潜在遗传学，以及介于经典东部和西部路线之间的路线对亚种生存和维持的影响。许多无线电塔由学校主持。因此，该项目的研究主题和基础设施也将被用作美洲小学，中学和本科生教学资源的灵感。将为教师设计以迁徙和进化为重点的教育模块，以英语和西班牙语提供，并向国际学生提供画眉迁徙路线。这些模块将整合“科学的本质”教学法，并强调代表性不足的群体在STEM研究中的作用，同时将国际协调作为保护迁徙物种的关键。移民对物种形成的重要性在近三十年前就被提出，但受到的关注要少得多。许多移民在一起繁殖，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，这些系统中的杂交种预计会采取中间路线，使它们越过这些障碍，减少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。具体而言，用于跟踪鸟类的现有技术基础设施和开发用于以低覆盖率对数百个个体进行基因分型的基因组资源将用于（1）比较亲本和杂交画眉的存活率，（2）鉴定迁移性状的遗传变异，以及（3）测试针对杂交种的选择是否对这些变异起作用。没有直接测试迁移的物种形成的作用已经进行了日期，留下关键的差距，在我们的理解物种形成，考虑到迁移的差异是分类学上广泛的，可以帮助解释在温带地区的年轻物种对的优势。迁移也可能是一个令人信服的例子，一个外在的后合子隔离障碍，考虑到减少混合健身来自他们的中间行为和父母的环境之间的不匹配。外界隔离被认为在物种形成中很重要，但其在自然界中的程度尚不清楚，特别是在脊椎动物中。这项工作也将涉及物种形成以外的领域，包括复杂行为和保护的遗传学。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

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.