DISSERTATION RESEARCH: The role of integration in driving the morphological diversity of mammalian jaws

论文研究：整合在驱动哺乳动物颌骨形态多样性中的作用

• 批准号: 1501385
• 负责人: Elizabeth Dumont
• 金额: $ 2.01万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501385&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; role; integration; driving

Mammals are warm-blooded and so need to eat relatively large quantities of food to maintain their high metabolic rate. Teeth and jaws are the first point of contact with food, and different types of teeth and jaws are specialized for eating different kinds of foods. This relationship has led to a wide range of jaw shapes. For example nectar-eating bats have long and slender jaws for reaching into flowers, whereas spotted hyenas have short and sturdy jaws for crushing bones. Other factors unrelated to feeding can also influence the shape of the jaw, such as the need to make sounds for communication, and digging burrows. Despite these various roles, the shape of mammal jaws is limited by a number of things. Specialised diets (such as bone-crushing or feeding on nectar) often require very specific jaw shapes. Jaw shape is also determined by the genes available to control the way jaws grow. Both of these factors narrow the range of possible jaws shapes that mammals can have. This project investigates how jaw shapes are related to diet and how those shapes have evolved over time. Through this research we will learn how and why jaw shape is very diverse in some groups of mammals and very limited in others. This research will provide STEM training opportunities to undergraduate and high-school students, including women and under-represented minorities, and support science outreach programs in the local community.The mammalian jaw can be thought of as a functional tool for performing tasks related to feeding, communication, and competition. Developmental evidence suggests that there are two primary regions that can evolve independently, or modules, present in the mammalian jaw: the ramus and corpus. The ramus is the back portion of the jaw and serves as the site of muscle attachments. The corpus is the front portion of the jaw and houses the teeth. As modules become more independent of one another there is greater scope for increasing morphological diversity. However, the extent of co-variation among modules can differ both within and between species. These differences arise due to a variety of genetic and functional constraints. This study uses a combination of morphometric and phylogenetic comparative methods to investigate how modularity has influenced the range of jaw morphologies exhibited by mammals. This project will test two primary hypotheses: 1) the evolution of mammal jaws is characterized by repeated instances of convergence as a result of similarity in diets (i.e., functional demands) among different groups of species, and 2) mammalian jaw diversity is facilitated by reducing the level of co-variation among different modules within the jaw. By addressing these two hypotheses, this study aims to understand how constraints have influenced jaw diversity and how this diversity is distributed within the mammal clade

哺乳动物是温血动物，因此需要吃相对大量的食物来维持高代谢率。牙齿和颌骨是与食物的第一接触点，不同类型的牙齿和颌骨专门用于吃不同种类的食物。这种关系导致了各种各样的下巴形状。例如，食花蜜的蝙蝠有细长的下巴，可以伸入花朵，而斑鬣狗则有短而坚固的下巴，可以压碎骨头。与进食无关的其他因素也会影响下巴的形状，例如需要发出声音进行交流以及挖掘洞穴。尽管有这些不同的作用，哺乳动物下巴的形状仍受到许多因素的限制。特殊的饮食（例如碎骨或以花蜜为食）通常需要非常特定的下巴形状。下颌形状也由控制下颌生长方式的基因决定。这两个因素都缩小了哺乳动物可能拥有的下颌形状的范围。该项目研究了下颌形状与饮食的关系以及这些形状如何随着时间的推移而演变。通过这项研究，我们将了解如何以及为何在某些哺乳动物群体中下颌形状非常多样化，而在其他哺乳动物群体中则非常有限。这项研究将为本科生和高中生（包括女性和代表性不足的少数族裔）提供 STEM 培训机会，并支持当地社区的科学推广计划。哺乳动物的下巴可以被认为是执行与喂养相关的任务的功能性工具、沟通、竞争。发育证据表明，哺乳动物下巴中有两个可以独立进化的主要区域或模块：升支和语料库。升支是颌骨的后部，是肌肉附着的部位。语料库是颌骨的前部，容纳牙齿。随着模块之间变得更加独立，增加形态多样性的空间就更大。然而，模块之间的共变程度在物种内部和物种之间都可能不同。这些差异是由于各种遗传和功能限制而产生的。这项研究结合了形态测定和系统发育比较方法来研究模块化如何影响哺乳动物所表现出的颌部形态范围。该项目将测试两个主要假设：1）哺乳动物颌骨进化的特点是由于不同物种群体之间饮食（即功能需求）的相似性而出现重复的趋同现象，2）哺乳动物颌骨的多样性是由以下因素促进的：减少颌内不同模块之间的共变水平。通过解决这两个假设，本研究旨在了解限制因素如何影响颌部多样性以及这种多样性如何在哺乳动物进化枝内分布