CAREER: Empirically evaluating the genomic consequences of assisted migration in heterogeneous environments

应对人为气候变化既是一个社会学问题，也是一个科学问题。目前的研究表明，许多物种现在落后于不断变化的气候条件，与过去的条件相比，它们的表现很差。确定哪些物种受到了影响，物种减少的速度有多快，以及评估应对物种减少的潜在解决方案是关键目标。一种可能的解决方案是辅助迁移，即有意地将地理上遥远的种群中更能适应不断变化的条件的个体引入焦点种群。辅助迁移是有争议的，因为在向种群中引入新的变异时往往会有未知的后果，而且因为它在很大程度上没有通过对照实验进行测试。该奖项实验性地解决了在其分布的一小部分受到威胁的广泛植物中辅助迁移的后果。来自已经适应当代条件的种群的种子和幼苗将被引入焦点种群的一个子集。将这些实验种群与附近对照种群之间的性状、基因组和种群成功进行比较，将提供迄今为止收集到的关于辅助迁移效率和潜在效用的最佳经验数据。该奖项还通过为中等教育教师提供在课堂上解决这一问题所需的技能、课程计划和信息，解决了美国公众对气候变化的更多了解。该奖项资助创建一个动态游戏式的气候变化外展模块，一个研究生领导的科学外展团队，进入中学教育教室，以及一个研讨会课程，指导有抱负的STEM教师如何解决有争议的问题。这里授予的辅助迁移实验评估了三个主要问题：在引入之后，整个基因组中发生了多少渗入，以及这种渗入会持续多久？是基因渗入改变了性状分布还是使越界表型出现？在正常年份或极端年份，引进是否能提高本地种群的适应性？该项目通过利用模式生物Mimulus guttatus的基因组资源来解决这些问题。初步数据表明，海拔匹配的加利福尼亚种群比俄勒冈瀑布种群具有更高的适应性，俄勒冈瀑布种群在极端气候年面临灭绝的危险。这个项目将加利福尼亚的种群引入到过去三年跟踪的12个种群的子集中。采用低覆盖率全基因组测序方法，追踪引进种群在引进后三年内特有的遗传变异，调查引进后渗入的数量和时间。一个多年的普通花园实验，每年在实验期间收集种子，用于评估辅助迁移后表型和适合度的变化。虽然这个实验对保护界提供了重要的价值，但它也将提供新的见解，了解进化力量如何在自然种群中相互作用，以消除和维持快速生态时间尺度上的多态性。该奖项资助培训五名本科生研究人员和一名研究生，主要通过多元化倡议以及通过针对多个年龄组的既定外展活动进行公共传播来招募。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。

Responding to anthropogenic climate change is both a sociological and a scientific issue. Current studies suggest that many species are now lagging behind changing climatic conditions and are doing poorly relative to past conditions. Determining which species are impacted, how fast species are declining, and evaluating potential solutions to counter declines are key goals. One potential solution is assisted migration, where individuals from a geographically-distant population that are better adapted to the changing conditions are intentionally introduced into a focal population. Assisted migration is controversial because there are often unknown consequences when introducing new variation into a population, and because it has largely been untested via controlled experiments. This award experimentally addresses the consequences of assisted migration in a widespread plant that is threatened in a small portion of its distribution. Seeds and seedlings from populations already adapted to contemporary conditions will be introduced into a subset of focal populations. Comparisons of traits, genomes, and population success between these experimental populations and nearby control populations will provide the best empirical data collected to date on the efficiency and potential utility of assisted migration. This award also addresses the need for greater public understanding of climate change across the U.S. by providing secondary education teachers with the skills, lesson plans, and information necessary to address this issue in the classroom. This award funds the creation of a dynamic game-like climate change outreach module, a graduate student-led science outreach team to go into secondary education classrooms, and a seminar course for aspiring STEM teachers to instruct teachers how to address contentious issues. The assisted migration experiment awarded here evaluates three main questions: how much introgression occurs across the genome following the introduction and how long does it persist? Does introgression shift trait distributions or enable transgressive phenotypes to emerge? Do introductions improve fitness of the native populations in normal or extreme years? This project addresses these questions by leveraging the genomic resources of a model organism, Mimulus guttatus. Preliminary data indicate that elevation-matched California populations have higher fitness than native Oregon Cascades populations, and that Oregon Cascades populations are in danger of extirpation in extreme climatic years. This project introduces California populations into a subset of twelve populations that have been followed for the last three years. The amount and timing of introgression following introduction will be surveyed by using low coverage whole genome sequencing to track genetic variants specific to the introduced populations over three years post-introduction. A multi-year common garden experiment with seeds collected each year during the experiment will be used to evaluate how phenotypes and fitness changes following assisted migration. While this experiment provides important value to the conservation community, it also will provide novel insights into how evolutionary forces interact within a natural population to remove and maintain polymorphism on rapid ecological timescales. This award funds training for five undergraduate researchers and a graduate student recruited primarily through diversity initiatives as well as public dissemination via established outreach events targeting multiple age groups.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.