DISSERTATION RESEARCH: Phenotypic plasticity and evolution in the pharyngeal jaw apparatus

表型可塑性，即基因相似个体在环境刺激下的发育变化，可能是生物多样化的一个关键特征。慈鲷是一个非常多样化的群体，也可能具有不同寻常的表型可塑性。这项工作是研究这些鱼类在形态、基因表达和蛋白质编码基因进化方面的表型可塑性的进化后果。目前的工作集中在一个群体，表现出两种不同的形态，在相同的人群中，在颌骨特征上有很大的不同。这种类型的变异可能代表了进化分化开始的中间阶段，具有这种多态性的物种通常比非多态性物种更具可塑性。这些鱼的颌部可塑性将通过实验操纵饮食来检验。下颌肌肉中基因表达水平随饮食变化的变化将通过高通量测序进行量化，并与非多态性物种的基因表达进行比较。这些分析将阐明在多态物种中的基因表达是否大于在较少变异物种中的基因表达的可塑性。这个项目将对物种之间形态分化的起源和速度产生广泛的见解。这项工作还将更好地理解所有脊椎动物共有的肌肉生长和萎缩的分子途径。学生将接受培训，并将开展K-12外展活动。

Phenotypic plasticity, developmental change within genetically similar individuals in response to environmental stimuli, could be a key feature in biological diversification. Cichlid fishes are an exceptionally diverse group that also might be unusually phenotypically plastic. This work is investigating the evolutionary consequences of phenotypic plasticity in morphology, gene expression, and evolution of protein-coding genes in these fishes. The current work is focused on a group that exhibits two alternative morphologies in the same populations that differ extensively in jaw characters. This type of variation could represent an intermediate stage in how evolutionary divergence begins, and species with this type of polymorphism might generally be more plastic than non-polymorphic species. Plasticity in the jaws of these fish will be examined using experimental manipulations of diet. Changes in the level of gene expression in the jaw muscles in response to diet will be quantified using high-throughput sequencing and compared to gene expression in a non-polymorphic species. These analyses will shed light on whether gene expression in a polymorphic species is greater than plasticity in gene expression in a less variable species. This project will produce broad insight into the origin and pace of morphological divergence among species. This work will also provide a better understanding of the molecular pathways involved in muscle growth and atrophy that are shared across all vertebrates. Students will be trained, and K-12 outreach will occur.