Mechanisms of environmental acclimation and adaptation in fish

我的研究计划的长期目标是了解鱼类用来应对环境变化的机制，以及这些机制在个体和种群中的差异。在接下来的六年里，我们将重点研究与有氧代谢调节相关的机制，因为有氧代谢是一个根本性的重要过程，众所周知，它塑造了动物的分布和丰度，甚至可能在新物种的产生中发挥作用。我们将研究大西洋千里鱼的可塑性和有氧代谢的种内变异的机制。这是实现我们的研究目标的理想物种，因为我们之前已经表明，千里鱼在有氧代谢方面表现出相当大的可塑性，以应对温度和氧气水平的变化：两个环境因素对鱼类极其重要。此外，我们还发现北方种群的有氧代谢率和发育率高于南方种群，但它们对低氧水平的耐受能力较差。相比之下，北方种群的千里鱼能够增加线粒体的数量，线粒体是负责有氧新陈代谢的细胞器，以应对寒冷的温度，而来自南方种群的千里鱼则无法做出这种补偿反应。我们建议的研究利用有氧代谢的多个方面的这种差异，作为了解有氧代谢环境变化反应的基础机制的窗口。我们提出的研究分为三个相互关联的主题，其中我们将检查：1)有氧代谢的可塑性和种内变异，2)有氧代谢变异在早期发育中的作用，以及3)有氧代谢变异与耐低环境氧能力之间的关系。我们将研究在不同时间尺度上发生的反应，包括在几天到几个月的时间尺度上发生的表型可塑性引起的反应，以及由于多年发生的适应性进化而导致的不同种群之间的反应。我们建议使用先进的基因组学方法，结合详细的生化和生理分析，特别强调线粒体的功能。总之，这项研究将为有氧代谢在短时间和长时间尺度上对温度和氧气水平变化做出反应的遗传、生理和分子机制提供新的见解，并揭示鱼类用来应对环境变化的机制。这项基础性工作特别重要，因为这种机械知识可以用来帮助预测鱼类对全球气候变化和人类活动造成的环境退化影响的可能反应。

The long-term goal of my research program is to understand the mechanisms that fish use to cope with environmental change, and how these mechanisms vary among individuals and populations. In the next six years, we will focus on mechanisms related to the regulation of aerobic metabolism because aerobic metabolism is a fundamentally important process that is known to shape the distribution and abundance of animals and that may even play a role in the generation of new species. We will examine the mechanisms underlying plasticity and intraspecific variation in aerobic metabolism in Atlantic killifish, Fundulus heteroclitus. This is an ideal species in which to pursue our research objectives because we have previously shown that killifish exhibit substantial plasticity in aerobic metabolism in response to changes in temperature and oxygen levels: two environmental factors are extremely important for fish. In addition, we have shown that northern populations of killifish have higher aerobic metabolic rate and development rate than do southern populations, but they have poorer ability to tolerate low oxygen levels. In contrast, northern populations of killifish are able to increase the amount of mitochondria, the organelle responsible for aerobic metabolism, in response to cold temperatures, while killifish from southern populations cannot mount this compensatory response. Our proposed research takes advantage of this variation in multiple aspects of aerobic metabolism as a window into the mechanisms that underlie the responses of aerobic metabolism environmental change. Our proposed research is divided across three interrelated themes in which we will examine: 1) plasticity and intraspecific variation in aerobic metabolism, 2) the role of variation in aerobic metabolism during early development, and 3) the relationship between variation in aerobic metabolism and the ability to tolerate low environmental oxygen. We will examine responses that occur at various time scales, including responses due to phenotypic plasticity that occur on a time-scale of days to months, and responses that vary between populations as a result of changes due to adaptive evolution that occur over many years. We propose to use cutting-edge genomic methods combined with detailed biochemical and physiological analyses, with a particular emphasis on mitochondrial function. Together this research will provide novel insights into the genetic, physiological and molecular mechanisms underlying the responses of aerobic metabolism to changes in temperature and oxygen levels on both short and long time scales and reveal the mechanisms that fish use to cope with environmental change. This fundamental work is particularly important because this mechanistic knowledge can be used to help predict the likely responses of fishes to the effects of global climate change and environmental degradation due to human activities.