Phylogenetics and Evolutionary Biomechanics of Coral Reef Fishes

Labridae科鱼类是一个多样化的群体，有近600种，生活在世界各地的热带和温带海洋水域，构成了珊瑚礁多样性的主要部分。我们对模糊家谱的理解和摄食行为的生物力学研究的进展将有助于探索珊瑚礁鱼类的进化。该项目的第一个目标是收集Labridae中几个物种组的新DNA序列数据。在NSF之前的支持下，使用115个物种的数据生成了Labridae的家谱。基于来自细胞不同部位（线粒体和细胞核各2个）的4个基因，该树的系统发育关系得到了很好的解析。然而，有几个大的物种群仍未得到解决。在这个项目中，将为120个额外的分类群获得适合物种水平问题的基因序列。此外，该项目还将研究与鱼头骨早期生长和发育有关的两个基因。这些基因包括Otx1和Dlx2，前者在头部生长中起作用，后者参与下颌形成和牙齿发育。这些基因的序列将在50个物种中收集，具有不同的头骨结构和颌骨解剖结构。因此，这项研究将提供来自许多物种和许多基因的新信息，其中一些已知的调控参与了动物的关键部分——头骨的形成。该提案的第二个目标是将进化树与工程设计和摄食行为知识的概念结合起来研究头骨功能。进化趋同的特定假设将被测试，以确定相同的工程解决方案是否已经在该群体的历史中多次实现。在这个家族中发现的颌骨和头骨的极端变化使它们成为颅骨结构和功能进化的模型系统。生物力学工程模型允许计算基本喂养力学，如颌闭合力和速度，以及颌突。作为物理结构和计算机模型生成的生物力学模型对研究和教育都很有用。结合许多物种的进化和功能，该项目将研究地球上最多样化的脊椎动物辐射之一的生物力学的进化变化。从基因到组织再到整个生物体，对生物结构和功能的综合理解是生物学的主要前沿之一。该项目通过使用分子系统发育学和工程概念测试功能进化的特定假设，有助于实现这一目标。该项目以多种方式为教育、培训、展览和研究基础设施做出贡献。首席研究员在芝加哥大学教授本科课程，每年在菲尔德博物馆举办实验练习。在大学，研究生和博士后水平的学生参与拟议的研究的各个方面，包括测序，分析和生物力学。目前正在与来自奥地利、澳大利亚、智利、肯尼亚、马达加斯加、新西兰、菲律宾和泰国的人员进行合作。博物馆展出的展品是由美国国家科学基金会资助的研究开发的鱼头功能模型，并计划在菲尔德博物馆展出系统发育和功能研究。PI在博物馆举办讲座，在公共广播电台发表演讲，访问当地学校，并向芝加哥地区的长者旅社和扶轮社等团体介绍珊瑚礁鱼类生物学。本提案中采用的动物功能的物理模型和计算机模型是课堂教育、研究培训和博物馆展览的绝佳工具。

Fishes of the family Labridae are a diverse group of nearly 600 species that inhabit tropical and temperate marine waters throughout the world and constitute a major segment of the diversity found on coral reefs. Advances in our understanding of the labrid family tree and study of the biomechanics of feeding behavior will allow exploration of evolution in coral reef fishes. The first goal of this project is to collect new DNA sequence data for several species groups within the Labridae. With previous NSF support, a family tree for the Labridae was generated using data for 115 species. Resolution of phylogenetic relationships on this tree was excellent based on four genes from different parts of the cell (2 each from the mitochondrion and the nucleus). However several large species groups remain unresolved. In this project, sequences of genes that are appropriate for species-level questions will be obtained for 120 additional taxa. In addition, this project will investigate two genes involved in early growth and development of fish skulls. These include Otx1, a gene that plays a role in head growth and Dlx2, a gene involved in both lower jaw formation and tooth development. Sequences for these genes will be collected in 50 species, having diverse skull structures and jaw anatomy. Thus, this study will provide new information from many species and many genes, some of which have known regulatory involvement in building a key part of the animal, the skull. The second objective of the proposal is to combine evolutionary trees with concepts from engineering design and knowledge of feeding behavior to study skull function. Specific hypotheses of evolutionary convergence will be tested to determine whether the same engineering solution has been achieved multiple times in the history of the group. The extreme modifications of jaws and skull found in this family make them a model system for evolution in cranial structure and function. Biomechanical engineering models allow calculation of basic feeding mechanics such as jaw closing force and speed, and jaw protrusion. Biomechanical models, generated as physical constructs and computer models, are useful for research and education. Combining evolution with function in many species, this project will examine evolutionary change in the biomechanics of one of the most diverse radiations of vertebrates on Earth. The movement toward an integrated understanding of biological structure and function, from genes to tissues to whole organisms, is one of the major frontiers of biology. This project contributes to that goal by testing specific hypotheses of functional evolution using molecular phylogenies and engineering concepts. This project contributes to education, training, exhibits, and research infrastructure in many ways. The Principal Investigator teaches undergraduate courses at the University of Chicago and lab exercises are held each year in the collections of the Field Museum. Students at the college, graduate, and postdoctoral levels are involved with all aspects of the proposed research, including sequencing, analysis, and biomechanics. Collaborations are underway with people from Austria, Australia, Chile, Kenya, Madagascar, New Zealand, The Philippines, and Thailand. Museum exhibits are now on display that feature models of fish head function developed from NSF-funded research, and exhibits are planned to feature both phylogenetic and functional research at the Field Museum. The PI gives museum lectures, has spoken on public radio, visits local schools, and presents coral reef fish biology to groups such as Elder Hostel and Rotary in the Chicago area. Physical and computer models of animal function featured in this proposal are fantastic tools for classroom education, research training, and museum exhibits.