Prospective and Retrospective Studies on Plant Evolutionary Response to Climate Change

加拿大气候变暖的最后一幕发生在更新世之后，持续了数千年。物种从南方的冰川避难所中走出来时，经历了许多世代的进化重新适应北纬。目前的气候变化是几十年来发生的，一些物种只有通过对条件突变的快速进化反应才能持续存在。至关重要的是，关于保护生物多样性和生态系统服务的实际决定必须以关于进化潜力的基本证据为依据。需要测试案例，探索由遗传变异设置的适应性进化的限制，以及恢复这些限制的保护措施的有效性。我们将探索3个与进化极限相关的主题，为5名研究生和30多名本科生提供培训机会-HQP为做出这些决定的一代人提供。*主题1.物候差异、基因流动和制约一些人提出，通过辅助基因流(AGF)将南方迁徙(在基因上适应热应激)转移到不断下降的北方种群中，可以增强被压抑的遗传变异。概念简单，实际问题可能会使AGF的实施复杂化。我们将进行实验，模拟AGF的初始阶段，以解决因常住人口下降和救援移民之间的开花时间差异而产生的问题。一个项目实地测试了从开花时间重叠估计居留-迁徙杂交率的定量方法。另一项研究探讨了将南方迁徙的耐热性引入北方人口的困难，这是由于耐受性空间和生殖时机之间的内在联系不平衡造成的。最后，第三个项目考察了开花时间和花粉质量之间的多效性的后果，这是由我实验室最近的发现推动的。*主题2.在进化拯救的背景下，适应度的平均适合度和加性遗传方差“。如果进化反应可以恢复平均绝对适合度，那么从气候变化中解救出来的可能性就会增加。环境变化会降低平均适合度。适合度中的加性遗传方差会发生什么？在什么时候，它可能会下降到如此低的水平，从而阻止足够的进化反应？在历史上典型和新颖的条件下，将对白菜纯种种群的种子/幼苗存活和种子生产进行评估。ASTER分析的新扩展将估计适合度的育种值的方差分量。*主题3.复活方法测量表型进化。对表型进化最直接的考验是在共同的环境中培养祖先和后代。我们将首先利用项目基线种子档案进行复活实验，以检测随着气候变化的进展而进行的进化。

Canada's last episode of climate warming, following the Pleistocene, played out across millennia. Species had many generations for evolutionary re-adjustment to northern latitudes as they emerged from glacial refugia in the south. Current climate change is occurring over decades, and some species will persist only through rapid evolutionary response to abrupt changes in conditions. It is crucial that practical decisions on preservation of biodiversity and ecosystem services be informed by basic evidence on evolutionary potential. Test cases exploring limits on adaptive evolution set by genetic variance, and efficacy of conservation measures to relive those limits, are needed. We will explore 3 themes related to evolutionary limits, giving training opportunities for 5 graduate students and over 30 undergraduates - HQP for the generation that will make those decisions. ***Theme 1. Phenological divergence, gene flow and constraint. Some suggest that depressed genetic variance can be enhanced by Assisted Gene Flow (AGF)translocate southern migrants (genetically adapted to thermal stress) into declining northern populations. Simple in concept, practical issues can complicate AGF implementation. We will do experiments to mimic initial stages of AGF to resolve issues arising from flowering time divergence between the declining resident population and the rescuing' migrants. One project field-tests quantitative methods to estimate resident-migrant hybridization rates from overlap in flowering schedules. Another examines difficulties of introgressing thermal tolerance from southern migrants into a northern population arising from the inherent linkage disequilibrium across space of tolerance and reproductive timing. Finally, a third project examines the consequences of pleiotropy between flowering time and pollen quality, prompted by recent discoveries in my lab. ***Theme 2. Mean fitness and the additive genetic variance in fitness, in the context of evolutionary rescue'. The probability of rescue' from climate change increases if evolutionary response can restore a mean absolute fitness to >1. Environmental shift will lower mean fitness. What will happen to the additive genetic variance in fitness? At what point might it fall so low as to prevent a sufficient evolutionary response? Seed/seedling survival and seed production will be evaluated in pedigreed populations of Brassica rapa under historically typical and novel conditions. A new extension of aster analysis will estimate variance components of the breeding value for fitness.***Theme 3. The resurrection approach measures phenotypic evolution. The most direct test for phenotypic evolution is by growing ancestral and descendent generations in a common environment. We will make first use of the Project Baseline seed archive to perform resurrection experiments to detect evolution in progress as climate change proceeds.