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: $ 3.79万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744766
• 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.

了解不同种群在其物种分布过程中如何对不断变化的环境条件作出反应是鱼类保护的基础。温度是决定鱼类分布的主要环境因子之一。表型可塑性沿着基因组分化，导致沿着环境梯度的种群间耐热性表型表达差异。导致鱼类对高水温的群体特异性反应的机制知之甚少。我的研究计划的长期目标是确定参与群体特异性耐热性差异的生理机制，并描述鱼类在大环境梯度中局部适应的生理特征。我将使用基因表达谱和生理评估，以确定整个自然和引进范围的鱼类种群对高水温的反应。除了其重要的文化，经济和生态重要性，奇努克鲑鱼（Oncorhynchus tshawytscha）是理想的研究与耐热性相关的生理机制，由于其大的原生范围和不同的热分布。此外，奇努克鲑鱼已被放养在其自然分布之外的系统中（例如，北美的五大湖），提供了一个极好的机会来调查物种如何迅速适应新的环境。本研究的近期目标是：1）研究高水温对鱼类早期发育阶段的影响，以及在幼鱼期表现的表型; 2）比较不同种群在自然和引进范围内对高水温的生理和转录组反应; 3）鉴定与种群间温度适应相关的变异-基因组分化的标志。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的影响，热耐受性与种群之间的基因组变异进行评估。这项创新工作的意义和影响是它的环境条件，可塑性和适应性分歧如何有助于鱼类种群之间的表型差异的综合。这项工作将推进我们的理解，特定人群的阈值在外温动物的热应力反应，这将产生一个框架，预测未来的气候变化和极端温度的后果，在加拿大的水生物种的保护。