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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654575
• 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.

*了解不同种群如何在其物种分布的整个过程中对不断变化的环境条件做出反应，是保护鱼类的基础。温度是决定鱼类分布的主要环境因子之一。表型可塑性和基因组差异导致热耐受表型在环境梯度上的不同种群间表达的差异。导致鱼类对高水温做出种群特异性反应的机制还知之甚少。我的研究计划的长期目标是确定种群特有的热耐性差异所涉及的生理机制，并表征鱼类跨越大环境梯度的局部适应的生理特征。我将使用基因表达谱和生理评估来确定自然和引入范围内的鱼类种群对高水温的反应。除了具有重要的文化、经济和生态意义外，Chinook鲑鱼(Oncorhynchus Tshawytscha)由于其广泛的原生范围和不同的热量分布，是研究与热耐受相关的生理机制的理想物种。此外，奇努克鲑鱼在其自然分布之外的系统(如北美五大湖)被放养，这为研究物种适应新环境的速度提供了一个极好的机会。这项研究的短期目标是：1)检测在早期发育阶段暴露于高水温对鱼类的影响，以及后期表现为幼鱼的表型；2)比较不同种群在其自然和引进范围内对高水温的生理和转录范围的反应；3)确定与种群之间的温度驯化相关的变化--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，使用控制环境影响的实验方法，将评估与种群间基因组变异相关的耐热性。这项创新工作的意义和影响在于它综合了环境条件、可塑性和适应性差异如何导致鱼类种群之间的表型差异。这项工作将促进我们对温带生物特定种群的热应激反应阈值的理解，这将为预测未来气候变化和极端温度对加拿大水生物种保护的后果提供一个框架。