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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681622
• 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整个物种分布的环境条件的响应是对鱼类保护的基础。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会导致沿环境梯度在人群中表达的热耐受性表型的差异。人们对鱼类水温高水温的特定反应的机制知之甚少。我的研究计划的长期目标是确定与人口特异性差异有关的生理机制，并表征大型环境梯度跨鱼类局部适应的生理特征。我将使用基因表达分析和生理评估来确定在其自然和引入范围的鱼类种群中对高水温的反应。除了其重要的文化，经济和生态重要性外，奇努克鲑鱼（Oncorhynchus tshawytscha）是研究与热耐受性相关的生理机制，这是由于其天然范围较大和不同的热分布所致。此外，奇努克鲑鱼已经在自然分布以外的系统（例如北美大湖区）以外的系统中存入，提供了一个很好的机会，可以调查物种如何适应新环境的速度。这项研究的短期目标是：1）检查在早期发育阶段暴露于高水温对鱼类的影响，而表型后来表示为少年； 2）比较整个自然和引入范围的不同人群的高水温的生理和转录组的反应； 3）确定与种群中温度适应相关的变化 - 基因组差异的标志。自然界观察到的热应力反应的差异通常受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，将评估与种群之间基因组变异相关的热耐受性。这项创新工作的重要性和影响是其综合环境条件，可塑性和适应性差异如何促进鱼类种群的表型差异。这项工作将促进我们对Ectotherms热应力反应的特定人群特异性阈值的理解，这将产生一个框架，以预测加拿大加拿大水生物种保护水生物种的后果和极端温度的后果。