The role of phenotypic plasticity and resource polymorphism on the evolution of fish populations

达尔文的《物种起源》首次阐述了物种多样性和物种形成的机制，过去几年发表的评论强调，这个问题仍然是进化生态学中最具挑战性和最令人兴奋的问题之一。已有研究表明，可塑性通过单一基因对不同环境条件产生不同表型的能力来促进新表型的产生。表型可塑性被认为是资源多态表达的一种机制，即同一种群的个体在形态、行为和生理特征上表现出与不同生态位使用相关的差异。资源的多态反过来会导致遗传分化，最终导致适应性辐射。然而，在自然系统中测试这些最新的理论发展仍然是进化生态学中最具挑战性的任务之一。我的研究计划的长期目标是研究表型可塑性和资源多态如何促进适应性辐射。我使用来自加拿大盾湖的溪流鲑鱼，Salvelinus fontinaris作为模式物种。小河鲑鱼呈现出一种微妙的资源多态，我们的结果表明，这些湖泊代表了该物种进化分化的早期阶段。这使得它们对了解生态物种形成早期步骤所涉及的过程特别感兴趣。这项拟议的研究建立在该系统15年的工作基础上，将使我们能够1)提高我们对温度在温带生物资源多态进化中的作用的理解，2)测试两个离散生态型中表型-环境之间的功能关系，3)确定鱼类适应性特征传递的潜在机制。除了在自然种群上进行研究外，拟议的研究项目在概念上是原创的，将共同有助于更好地了解动物适应性辐射的机制。此外，拟议的研究将允许培养两名理科硕士。以及两名博士生和10名研究助理。这些学生将获得扎实的概念和实践技能，这些技能受到公共组织、私营行业和学术机构等雇主的高度欢迎。

Understanding the mechanisms underlying species diversification and speciation was first addressed in Darwin's The Origin of Species, and reviews published over the past few years have highlighted that this question is still one the most challenging and exciting issues in evolutionary ecology. It has been shown that plasticity promotes the origin of novel phenotypes through the capacity of single genotypes to produce different phenotypes in response to varying environmental conditions. Phenotypic plasticity has been proposed as a mechanism for the expression of resource polymorphism, i.e., when individuals of the same population exhibit differences in morphology, behaviour, and physiological traits associated with differential niche use. Resource polymorphisms could in turn lead to genetic differentiation and ultimately to adaptive radiation. However, testing these recent theoretical developments in natural systems is still one of the most challenging tasks in evolutionary ecology. The long-term objective of my research program is to study how phenotypic plasticity and resource polymorphism promote adaptive radiation. I use the brook trout, Salvelinus fontinalis, from Canadian Shield lakes as the model species. Brook trout exhibits a subtle resource polymorphism, and our results suggest that these lakes represent the early stages of evolutionary divergence of this species. This makes them of particular interest for understanding the processes involved in the early steps of ecological speciation. The proposed research is built on 15 years of work in this system and will allow us to 1) improve our understanding on the role of temperature in the evolution of resource polymorphism in ectotherms, 2) test the functional relationship between phenotype–environment in two discrete ecotypes, and 3) identify the mechanisms underlying the transmission of adaptive traits in fishes. In addition to being done on natural populations, the proposed research projects are conceptually original and will collectively contribute to a better understanding of the mechanisms of adaptive radiation in animals. Furthermore, the proposed research will allow to train two M.Sc. and two Ph.D. candidates as well as 10 research assistants. These students will acquire solid conceptual and practical skills, which are highly sought by employers like public organizations, private industries, and academic institutions.