Experimental evolution of phenotypic plasticity

所有的有机体都在多变的环境中生活和进化。个体在其一生中经历了不断变化的生物和非生物条件，并且种群在接下来的几代人中暴露在不同的环境中。我们经常观察到，生物体通过表现出表型可塑性来应对这种可变性，即表现出适应当前条件的不同形态、生理和/或行为的能力。不同的表型是由相同的基因产生的，因此依赖于基因组的不同使用。因此，表型可塑性是建立在特定环境基因调控的基础上的。生态学家和进化生物学家对表型可塑性进行了广泛的研究，其中感兴趣的是基因所表现出的可塑性程度、其数量遗传结构以及预测可塑性进化的条件。另一方面，分子生物学家和微生物学家已经收集了大量关于环境诱导表型的分子调控的信息。然而，我们目前缺乏弥合生态条件及其产生的选择压力之间差距的方法，以及另一方面塑料反应所需调控机制的分子细节。只有以这种综合的方式研究可塑性的进化，我们才能完全理解我们观察到的可塑性是如何由生态选择压力和基因调控的分子细节所施加的限制相互作用而形成的。在这里，我们提议开发一种在分裂酵母中的实验进化方法，以研究可塑性的进化。我们的实验策略将允许我们将单个基因的表达置于交替的相反选择压力下，并在表型和分子水平上跟踪环境特定调控的从头进化。在这个项目的过程中，我们将创建实验酵母菌株，进行试点实验以确定最佳的实验条件和程序，并进行进化实验，作为我们方法的实用性和威力的原则证明。同时，这项实验应该会产生即时感兴趣的可发表数据，并允许我们以最佳方式指导未来对进化反应的实验和分析。这里提出的工作将为更长期的研究计划奠定基础。我们正计划向研究委员会寻求资金，以探索进化可塑性的生态背景和分子细节，将生态制度产生的选择压力与基因调控的变化联系起来。

All organisms live and evolve in variable environments. Individuals experience changing biotic and abiotic conditions over the course of their life, and populations are exposed to different environments in successive generations. We often observe that organisms cope with this variability by showing phenotypic plasticity, the capacity to express different morphologies, physiologies and/or behaviours that are adapted to the current conditions. The different phenotypes are produced from the same genotype and therefore rely on the differential use of the genome. Accordingly, phenotypic plasticity is based on environment-specific gene regulation.Phenotypic plasticity has been extensively studied by ecologists and evolutionary biologists who were interested in, amongst others, the extent of plasticity shown by genotypes, its quantitative genetic architecture and the conditions under which plasticity is predicted to evolve. Molecular biologists and microbiologists, on the other hand, have gathered a large body of information on the molecular regulation of environment-induced phenotypes. However, we are currently missing approaches that bridge the gap between ecological conditions and the selection pressures they generate on the one hand, and the molecular details of the regulatory mechanisms required for a plastic response on the other. Only by investigating the evolution of plasticity in such an integrated way will we be able to gain a complete understanding how the plasticity we observe is shaped by the interplay between ecological selection pressures and constraints imposed by the molecular details of gene regulation.Here we propose to develop an experimental evolution approach in fission yeast, Schizosaccharomyces pombe, to study the evolution of plasticity. Our experimental strategy will allow us to subject the expression of a single gene to alternating opposing selection pressures and follow the de novo evolution of environment-specific regulation at the phenotypic and molecular levels.During the course of this project we will create experimental yeast strains, conduct pilot experiments to define optimal experimental conditions and procedures, and perform an evolutionary experiment that will serve as proof-of-principle for the utility and power of our approach. This experiment should at the same time generate publishable data of immediate interest and allow us to optimally direct future experiments and analyses of evolutionary responses.The work proposed here will lay the foundations of a longer-term research programme. We are planning to seek funding from Research Councils to explore the ecological context and molecular details of evolving plasticity, linking selection pressures generated by ecological regimes to changes in gene regulation.