Regulatory control of phenotypic plasticity: Analysis of the molecular basis of stressor-induced adaptation processes in the aquatic keystone species Daphnia

该项目旨在了解环境如何与基因组相互作用（并形成），以及基因组调控和变异如何与表型可塑性和表型进化相关联。它特别关注在新的模式生物水蚤（Daphnia pulex）中，由环境中的化学信号诱导的特征的阶段依赖性、组织特异性和可逆性形态发展。到目前为止，我们对常见形态变异（如表型可塑性）的机制基础的理解只是零碎的，因为在确定控制表型变异的细胞控制机制的经验模式方面取得的成功相对较少。这主要是因为确定复杂性状的遗传结构具有挑战性，因为塑性发育通常不依赖于少数可塑性或稳健性基因，而是源于多个环境敏感成分和可能由许多基因座控制的途径之间的相互作用。为了阐明在分子水平上驱动塑性反应表达的细胞机制，我将采用最先进的组学方法和计算机方法的独特组合。为了揭示可塑性发育反应的基因组基础，计划的研究将利用杰出的模式生物水蚤。为了响应捕食者释放的化学信号（即kairomones），该物种表现出惊人的诱导防御能力，包括发育阶段依赖、组织特异性和可逆的新生形态形成。通过对不同基因型和发育阶段的适应性和可塑性性状的表达进行功能基因组分析，该项目的总体目标是为生物体如何应对环境挑战提供新的见解。因为水蚤是池塘和湖泊的重要物种，这项研究将最终改变我们目前对种群和生态系统对环境变化的缓冲能力的理解。

The proposed project aims to understand how the environment interacts with (and shapes) genomes, and how genome regulation and variation are linked to phenotypic plasticity and phenotypic evolution. It focuses specifically on the stage-dependent, tissue-specific and reversible morphological development of traits that are induced, in the new model organism, Daphnia pulex, by chemical signals from their environment. So far, our understanding of the mechanistic basis of common morphological variation such as phenotypic plasticity is only fragmentary as there has been relatively little success at identifying empirical patterns of cellular control mechanisms governing phenotypic variation. This is predominantly due to the fact that determining the genetic architecture of complex traits is challenging since plastic development typically does not rely on a few plasticity or robustness genes but rather arises from interactions between multiple environmentally sensitive components and pathways that might be controlled by many loci. To elucidate the cellular machineries that drive the expression of plastic responses at the molecular level, I will employ a unique combination of state-of-the-art omic methodologies and in silico approaches. To unravel the genomic underpinnings of plastic developmental responses planned research will make use of the outstanding model organism Daphnia pulex. In response to chemical cues released by predators (i.e., kairomones) this species exhibits an astonishing repertoire of inducible defences including developmental, stage dependent, tissue-specific and reversible de novo morphological formations. By conducting functional genomic assays across genotypes and developmental stages that differ in expression of the adaptive and plastic traits, the overarching goal of the proposed project is to provide novel insights into how organisms can and do respond to environmental challenges. Because Daphnia is a keystone species of ponds and lakes, this study will ultimately transform our current understanding of the buffering capacity of populations and ecosystems to environmental changes.