Prospective and Retrospective Studies on Plant Evolutionary Response to Climate Change

植物进化对气候变化响应的前瞻性和回顾性研究

• 批准号: RGPIN-2016-06540
• 负责人: Weis, Arthur
• 金额: $ 3.21万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616374
• 关键词: Prospective; Retrospective; Studies; Plant; Evolutionary

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.

加拿大上一次气候变暖是在更新世之后，持续了几千年。当物种从南方的冰川避难所出现时，它们经历了许多代的进化，重新适应北方纬度。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生存下来。至关重要的是，有关保护生物多样性和生态系统服务的实际决定应参考有关进化潜力的基本证据。需要测试案例来探索遗传方差对适应性进化的限制，以及保护措施对重温这些限制的效力。我们将探索与进化极限相关的3个主题，为5名研究生和30多名本科生提供培训机会--为做出这些决定的一代提供HQP。 主题1.物候趋异、基因流与限制。一些人认为，抑郁症的遗传变异可以增强辅助基因流（AGF）-易位南方移民（遗传适应热应力）到下降的北方人口。概念简单，但实际问题可能使AGF的实施复杂化。我们将做实验来模拟AGF的初始阶段，以解决由于常住人口下降和“救援”移民之间的开花时间差异而产生的问题。一个项目实地测试定量方法，以估计居民移民杂交率重叠开花时间表。另一个研究的困难渐渗的热耐受性从南部移民到北方人口所产生的内在连锁不平衡跨越空间的耐受性和生殖时间。最后，第三个项目研究了开花时间和花粉质量之间多效性的后果，这是由我实验室最近的发现引起的。 主题2.在“进化拯救”的背景下，平均适应度和适应度的加性遗传方差。如果进化反应可以将平均绝对适应度恢复到>1，那么从气候变化中“拯救”的概率就会增加。环境变化会降低平均适应度。适应度的加性遗传方差会发生什么变化？在什么时候它会下降到如此之低，以至于阻止了充分的进化反应？种子/幼苗存活和种子生产将在历史上典型的和新的条件下，在芜菁的纯种群体进行评估。aster分析的一个新扩展将估计适合度育种值的方差分量。 主题3.复活方法测量表型进化。对表型进化最直接的测试是在一个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，以检测气候变化过程中的进化。