Collaborative research: Understanding the role of developmental bias in the morphological diversification of bat molars

动物形态的进化是不平衡的，断断续续地辐射，探索某些形态而不探索其他形态。为什么这种模式存在一直是生物学中的一个基本问题。一种可能的解释可以从动物从卵成长为成年动物的方式的本质中找到，也就是说，在它们的发育过程中。控制动物发育的基因在网络中相互作用。这些网络中的一些基因与许多其他基因相互作用，而其他基因则更外围和孤立。该项目验证了这样一种假设，即动物形态的大多数进化是通过外围网络成分的变化以及这些外围成分形成的形态方面的变化发生的，而中心基因及其相关形态在物种中是保守的。为了验证这一假设，该项目调查了一个生态多样化的动物群体——夜蝠的牙齿进化模式和驱动因素。这个项目有望成为第一个描述控制动物形态的基因网络组织，以及这种组织对进化进行方式的影响的项目。因此，这个项目有望阐明在地球生命史上塑造动物进化的机制。该项目还将直接增加来自代表性不足群体（urm）的学生参与研究，并为公共教育做出贡献。这些目标将通过让来自波多黎各的大学管理学院本科生参与项目研究、在大学管理学院指导下培训博士后科学家以及在伯克博物馆展示项目成果来实现。该项目的目标是描述和模拟发育中的GRN模块及其形态的演变，使用夜狐蝠及其磨牙的辐射作为模型系统。该项目的核心假设是，磨牙GRN的保守核心模块控制了磨牙性状的初始形成，这些性状在物种间保守，网络子模块的进化修饰导致了种间形态变化。为了验证这一点，我们将完成两个目标。在Aim 1中，研究小组将量化发育中的下第一磨牙（m1）的形态学，这些磨牙是有代表性的夜猫子类动物，以及所有现存的夜猫子类动物的成年m1。这些数据将用于重建夜猫子m1形态的发育和进化，并确定在发育和进化时间内的保守和可变特征。在Aim 2中，该团队将绘制具有代表性的夜蛾类动物m1发育过程中的基因表达图谱，对关键臼齿发育途径中观察到的表达差异产生可变m1形态的能力进行功能测试，在计算空间中重建蝙蝠m1的GRN模块，并将GRN模块与m1形态多样性联系起来。利用来自这两个目标的数据，该团队还将使用机器学习技术对一个计算模型进行逆向工程，该模型将预测由发育模块变异引起的m1表型。通过这项研究，本项目将在适应性辐射中描述发育偏差在形态进化中的作用，在密切相关的物种中，基因表达的功能连接转移与形态进化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The evolution of animal form has been uneven, radiating in fits and starts, and exploring some forms but not others. Why this pattern exists has long been a fundamental question in biology. One possible explanation can be found in the very nature of the way that animals grow from an egg into an adult, i.e., in their development. The genes that control animal development interact in networks. Some genes in these networks interact with many other genes, while others are more peripheral and isolated. This project tests the hypothesis that most evolution in animal form occurs through changes in peripheral network components, and in the aspects of form that those peripheral components make, while central genes and their associated forms are conserved among species. To test this hypothesis, this project investigates the patterns and drivers of tooth evolution in an ecologically diverse animal group, noctilionoid bats. This project is expected to be among the first to characterize the organization of the gene networks that control animal form, and the impact that this organization has on the way evolution proceeds. This project is therefore expected to illuminate mechanisms that have shaped the evolution of animals over the history of life on earth. This project will also directly increase participation of students from underrepresented groups (URMs) in research and contribute to public education. These goals will be achieved by involving URM undergraduates from Puerto Rico in project research, training postdoctoral scientists in URM mentorship, and showcasing project results at the Burke Museum.This project’s goal is to characterize and model the evolution of developmental GRN modules and resulting morphologies, using the radiation of noctilionoid bats and their molars as a model system. This project's central hypothesis is that a conserved core module of the molar GRN controls the initial formation of molar traits that are conserved across species, with evolutionary modification of network sub-modules leading to interspecific morphological variation. To test this, two aims will be completed. In Aim 1, the team will quantify morphology of developing lower first molars (m1) in representative noctilionoids, and adult m1s across all extant noctilionoid genera. Data will be used to reconstruct the development and evolution of noctilionoid m1 morphology, and identify conserved and variable traits over developmental and evolutionary time. In Aim 2, the team will map gene expression over m1 development in representative noctilionoids, functionally test the ability of observed expression differences in key molar developmental pathways to generate variable m1 morphologies, reconstruct GRN modules for bat m1s in computational space, and link GRN modules to m1 morphological diversity. Using data from both aims, the team will also use machine-learning techniques to reverse-engineer a computational model that will predict m1 phenotypes resulting from variation in developmental modules. Through this research, this project will characterize the role of developmental biases in morphological evolution within an adaptive radiation, functionally link shifts in gene expression to the evolution of morphology among closely related species, and generate a predictive model for morphological evolution across a hyper-diverse mammal groupThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.