Physiological Signatures of Thermal Tolerance and Local Adaptation in Fishes

鱼类耐热性和局部适应的生理特征

• 批准号: RGPIN-2017-05479
• 负责人: Jeffries, Kenneth
• 金额: $ 1.89万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711663
• 关键词: Physiological; Signatures; Thermal; Tolerance; Local

Understanding how different populations respond to changing environmental conditions throughout their species' distributions is fundamental to the conservation of fishes. Temperature is one of the major environmental factors that determines the distributions of fishes. Phenotypic plasticity along with genomic divergence leads to differences in thermal tolerance phenotypes expressed among populations along environmental gradients. The mechanisms that lead to population-specific responses to high water temperatures in fishes are poorly understood. The long-term goal of my research program is to identify the physiological mechanisms involved in population-specific differences in thermal tolerance and to characterize the physiological signatures of local adaptation in fishes across large environmental gradients. I will use gene expression profiling and physiological assessments to identify responses to high water temperatures among fish populations throughout their natural and introduced ranges. In addition to their significant cultural, economic and ecological importance, Chinook salmon (Oncorhynchus tshawytscha) are ideal for studying the physiological mechanisms associated with thermal tolerance due to their large native range and disparate thermal distributions. Additionally, Chinook salmon have been stocked in systems outside of their natural distribution (e.g., Great Lakes of North America), providing an excellent opportunity to investigate how rapidly species can adapt to new environments. The short-term objectives of this research are: 1) to examine the effect of exposure to high water temperature on fishes during early developmental stages with the phenotype expressed later as juveniles; 2) to compare the physiological and transcriptome-wide responses to high water temperatures of different populations throughout their natural and introduced ranges; 3) to identify the variation associated with temperature acclimation among populations - a hallmark of genomic divergence. Differences in thermal stress responses observed in nature are generally influenced by environmental factors and genomic variation. Therefore, using experimental approaches to control environmental influences, thermal tolerance associated with genomic variation among populations will be assessed. The significance and impact of this innovative work are its synthesis of how environmental conditions, plasticity and adaptive divergence contribute to phenotypic differences among fish populations. This work will advance our understanding of population-specific thresholds for thermal stress responses in ectotherms, which will generate a framework for predicting the consequences of future climate change and extreme temperatures for the conservation of aquatic species in Canada.

了解不同种群如何应对其物种分布范围内不断变化的环境条件对于鱼类保护至关重要。温度是决定鱼类分布的主要环境因素之一。表型可塑性以及基因组差异导致沿环境梯度的群体之间表达的耐热性表型的差异。人们对导致鱼类对高水温产生特定群体反应的机制知之甚少。我的研究计划的长期目标是确定与特定人群耐热性差异相关的生理机制，并描述鱼类在大环境梯度下局部适应的生理特征。我将利用基因表达谱和生理评估来确定自然和引进范围内鱼类种群对高水温的反应。除了具有重要的文化、经济和生态重要性外，奇努克鲑鱼 (Oncorhynchus tshawytscha) 由于其广阔的原生范围和不同的热分布，是研究与耐热性相关的生理机制的理想选择。此外，奇努克鲑鱼已被放养在其自然分布范围之外的系统中（例如北美五大湖），这为研究物种适应新环境的速度提供了绝佳的机会。本研究的短期目标是： 1）研究暴露于高水温对早期发育阶段鱼类的影响，并在幼鱼后期表现出表型； 2）比较不同种群在其自然和引入范围内对高水温的生理和转录组范围的反应； 3）确定种群之间与温度适应相关的变异——这是基因组差异的标志。在自然界中观察到的热应激反应的差异通常受到环境因素和基因组变异的影响。因此，使用实验方法来控制环境影响，将评估与种群间基因组变异相关的热耐受性。这项创新工作的意义和影响在于它综合了环境条件、可塑性和适应性分歧如何导致鱼类种群之间的表型差异。这项工作将增进我们对变温动物热应激反应的特定人群阈值的理解，这将产生一个框架来预测未来气候变化和极端温度对加拿大水生物种保护的影响。