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

动物形态的演变是不均衡的，断断续续地辐射，探索一些形式而不是其他形式。这种模式为什么会存在，长期以来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子成长为成年动物的本质中找到，也就是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，即大多数动物形态的进化都是通过周围网络组件以及这些外围组件所形成的形式的变化来进行的，而中央基因及其相关形式在物种之间是保守的。为了验证这一假设，该项目调查了一种生态多样性的动物群体--夜行动物蝙蝠--的牙齿进化模式和驱动因素。该项目有望成为首批描述控制动物形态的基因网络组织的项目之一，以及该组织对进化进程的影响。因此，这个项目有望阐明在地球生命历史上塑造动物进化的机制。该项目还将直接增加来自代表不足群体(URM)的学生对研究的参与，并为公共教育做出贡献。这些目标将通过让波多黎各的URM本科生参与项目研究，在URM指导方面培训博士后科学家，并在Burke博物馆展示项目成果来实现。该项目的目标是以夜总会蝙蝠及其磨牙的辐射为模型系统，描述和模拟发育中的GRN模块和结果的形态的演变。该项目的中心假设是，磨牙GRN的保守核心模块控制着跨物种保守的磨牙特征的初始形成，网络子模块的进化修改导致物种间的形态变异。为了检验这一点，将实现两个目标。在目标1中，该团队将量化具有代表性的夜光体中发育的下第一磨牙(M1)的形态，以及所有现存夜光体属的成年M1的形态。数据将被用来重建夜蛾M1形态的发育和进化，并识别发育和进化过程中保守和可变的特征。在目标2中，该团队将绘制典型夜蛾M1发育过程中的基因表达图谱，从功能上测试在关键磨牙发育途径中观察到的表达差异产生不同M1形态的能力，在计算空间中重建BAT M1的GRN模块，并将GRN模块与M1形态多样性联系起来。使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反向工程，该模型将预测发育模块变化导致的M1表型。通过这项研究，该项目将表征发育偏差在适应性辐射下形态进化中的作用，在功能上将基因表达的变化与密切相关物种之间的形态进化联系起来，并为超多样化哺乳动物群体的形态进化生成预测模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.