DISSERTATION RESEARCH: The relative roles of selection and constraint in convergent ear loss across the true toads (Bufonidae)

中耳和外耳结构用于听到声音，并且为大多数陆地动物所共有。虽然青蛙和蟾蜍使用听觉来寻找配偶，但许多青蛙和蟾蜍已经失去了中耳和外耳结构。该项目旨在发现导致蟾蜍耳朵损失进化的遗传变化。由于其他陆地动物（包括人类）的中耳和外耳使用类似的发育途径，因此了解导致蟾蜍耳朵损失的遗传变化将阐明其他动物中耳和外耳损失和畸形的潜在原因。这项研究产生的遗传数据将有助于我们更好地了解蟾蜍物种之间的关系，并为未来的研究提供新的遗传数据。除了研究生培训，互动博物馆展示将从该项目产生的标本和数据，并将开发一系列的K-12课堂练习，以解释耳结构的演变在蟾蜍。该项目调查选择压力和遗传约束，产生收敛损失和潜在的恢复中耳和外耳结构在整个家庭的真正蟾蜍（蟾蜍科）。60蟾蜍物种（16无耳，44耳）跨越7个耳朵损失事件的序列数据将进行分析，以确定选择和平行的遗传变化的签名在50个基因参与中耳和外耳发育。该数据集将评估各种选择压力的影响，并在遗传水平上寻找约束的证据，补充研究团队先前收集的表型水平上的选择和约束的大量证据。该项目的结果将描绘选择和约束在蟾蜍科中驱动耳损失的作用，并阐明选择可以在受约束的，可能昂贵的，性状损失中起作用的共同遗传途径。

Middle and outer ear structures are used for hearing sound and are shared by most land animals. Although frogs and toads use hearing to find a mate, many frogs and toads have lost their middle and outer ear structures. This project aims to discover the genetic changes that have resulted in the evolution of ear loss in toads. Since the middle and outer ears of other land animals (including humans) use similar developmental pathways, understanding the genetic changes that result in ear loss in toads will illuminate potential causes of middle and outer ear loss and malformation in other animals. The genetic data produced by this study will help us better understand the relationships between toad species and provide novel genetic data for future research. In addition to graduate training, interactive museum displays will be created from the specimens and data generated from the project, and a series of K-12 classroom exercises will be developed to explain the ear structure evolution in toads.This project investigates the selection pressures and genetic constraints that generate convergent loss and potential regain of middle and outer ear structures across the family of true toads (Bufonidae). Sequence data for 60 bufonid species (16 earless, 44 eared) spanning seven ear loss events will be analyzed to identify signatures of selection and parallel genetic changes across 50 genes involved in middle and outer ear development. The dataset will assess the effects of various selection pressures and look for evidence of constraint at the genetic level, complementing the large amount of evidence for selection and constraint at the phenotypic level that has previously been collected by the research team. Results of this project will delineate the roles of selection and constraint in driving ear loss across Bufonidae, and elucidate common genetic pathways by which selection can act in a constrained, potentially costly, trait loss.