Arrival of the fittest: examining the underlying mechanisms of morphological plasticity in an adaptive radiation

学生战略优先领域：生物多样性关键词：进化，可塑性，基因表达，骨骼摘要：表型可塑性目前在进化生物学中引发了有争议的辩论。这场辩论涉及环境线索在产生生物多样性、物种以及最终标准达尔文综合(或其延伸)的效用方面的作用。虽然可塑性是一个与环境变化越来越相关的许多实证研究的主题，但我们仍然缺乏对进化系统中可塑性的潜在机制的普遍理解。这项研究将利用骨骼生物学的知识来填补这一空白，特别关注骨骼如何解释指导其生长和产生适应性变化的机械感觉刺激。骨生物学的一个核心教条是，骨细胞(机械感觉细胞)是骨骼对机械应力做出反应的唯一机制。然而，并不是所有有骨的动物都有骨细胞(大多数鱼类已经失去了骨细胞)，我们的初步数据指向了新兴的替代品。具体地说，我们之前的研究已经确定了非洲近缘物种之间骨骼可塑性的差异。慈鱼是进化生物学家的典范系统，因为它们来自最近的共同祖先，但表现出大量的适应性骨骼变异。这种变异似乎是由共同遗传背景上的一些突变控制的。到目前为止，我们已经将可塑性实验和QTL定位方法相结合，在头面部骨骼中识别了一些候选的可塑性基因。这些基因包括以前与骨骼发育有关的信号通路的成员(WNTS、BMPs、FGFs)，以及结构基因，包括RootBullet-初级纤毛的关键组成部分，代表着机械感觉功能的潜在替代机制。这些发现为理解可塑性的分子和细胞机制及其对进化的贡献提供了强有力的基础。

Studentship strategic priority area: BiodiversityKeywords: Evolution, plasticity, gene expression, boneAbstract: Phenotypic plasticity currently drives contentious debate in evolutionary biology. This debate deals with the role of environmental cues in generating biodiversity, species, and ultimately the utility of the standard Darwinian synthesis (or its extension). While plasticity is a topic of much empirical research with growing relevance to environmental change, we still lack a general understanding of the underlying mechanisms of plasticity in evolutionary systems. This studentship will draw on knowledge from bone biology to fill this gap, specifically focusing on how bones interpret the mechanosensory stimuli that instruct their growth and produce adaptive variation. A central dogma in bone biology is that osteocytes (mechanosensory cells) are the sole mechanism for bone to respond to mechanical stress. However, not all animals with bones possess osteocytes (most fishes having lost them), and there are emerging alternatives which our preliminary data point toward. Specifically, our previous research has identified variation in the magnitude of bone plasticity between related species of African cichlids. Cichlids are an exemplary system for evolutionary biologists in that they are derived from a recent common ancestor but exhibit vast amounts of adaptive skeletal variation. This variation appears to be controlled by a few mutations on a common genetic background. So far we have combined plasticity experiments with QTL mapping approaches to identify a number of candidate 'plasticity genes' in the craniofacial skeleton. These genes include members of signalling pathways previously implicated in bone development (Wnts, BMPs, FGFs), and structural genes including rootletin - a key component of the primary cilia and representative of a potential alternative mechanism for mechanosensory function. These findings provide a strong basis for understanding the molecular and cellular mechanisms involved in plasticity and their contribution to evolution.