The Physiological Basis of Allometry

它们身体部位的形状和大小是识别和定义不同物种的最重要的特征。然而，身体部位的形状和相对大小在发育过程中不断变化。因此，具有不同成年体型的个体通常在其身体部位的大小比例上存在差异。这种现象被称为异速生长。尽管异速生长已经被广泛地描述和研究了一个多世纪，但这些研究在很大程度上是描述性的，并且对不同身体部位的生长方式做出了简单而不切实际的假设。这在一定程度上是因为产生异速生长的生理过程仍然知之甚少，因为用于分析和解释异速生长的理论工具不能正确地推断生长过程。因此，控制身体各部分大小、形状和相对大小的机制仍然是生物学中未解之谜之一。拟议的工作将开发新的实践和理论工具，用于分析身体部位的相对大小如何以及为什么变化。了解器官如何生长到正确的大小和形状，对于理解正常发育和发育异常的原因和机制具有深远的意义。用户友好的软件将被开发并免费分发，这将允许学生和研究人员实现在本研究中开发的方程，并以新颖和更有效的方式分析异速生长。该项目将为研究生和本科生提供生物数学和生理学的跨学科培训。延伸到当地学校和区域科学博物馆，与昆虫生物学的讲座和实践练习，由服务不足的学校的初中学生参观实验室，并继续参与和指导北卡罗来纳生命和科学博物馆昆虫生物学，这是首席研究员的承诺的组成部分，传播科学，使NSF提供的资源更广泛地提供给当地社区。本研究有三个主要目的：(1)建立一个改进的静态异速生长理论和新的方程；(2)利用丰富多样的昆虫和哺乳动物数据集检验和验证该理论；(3)研究引起异速生长关系的生理因素。实验工作将集中于鳞翅目的翅体异速生长，鳞翅目对生长和大小的控制是最了解的。生长和大小受发育激素以及激素分泌的时间和持续时间的控制。这项工作将使用几个不同体型的雄性曼陀儿（Manduca sexta）遗传菌株，这些菌株可以在不同的温度和营养环境条件下饲养，这些环境条件也会影响体型和异速生长。这将产生一个丰富的数据集，允许对基因和环境对生长模式和由此产生的异速生长的影响进行功能性解释。这项工作的结果将使研究人员能够分析复杂的非线性异速发育的原因，并推断出导致这些异速发育的潜在生长模式。这项工作还将为遗传背景和环境变化改变大小、形状和异速生长的生理机制提供新的见解。

The shapes and sizes of their body parts are the most important features by which different species of animals are recognized and defined. The shapes and relative sizes of body parts, however, change continually during development. As a result, individuals with different final adult body sizes typically differ in the proportions of sizes of their body parts. This phenomenon is called allometry. Although allometry has been extensively described and studied for more than a century, those studies have been largely descriptive and have made simple and unrealistic assumptions about how different body parts grow. This is in part because the physiological processes responsible for producing allometries are still poorly understood and because the theoretical tools used to analyze and interpret allometries cannot deduce growth processes correctly. As a result, the mechanisms that control size, shape and the relative sizes of body parts remain among the great unsolved puzzles in Biology. The proposed work will develop new practical and theoretical tools for the analysis of how, and why, the relative sizes of body parts vary. Understanding how organs grow to their correct size and shape has profound implications for understanding the causes and mechanisms of normal development and of developmental abnormalities. User-friendly software will be developed and freely distributed that will allow students and researchers to implement the equations developed in this research and analyze allometries in novel and more productive ways. This project will provide interdisciplinary training in biological mathematics and physiology for a graduate student and a diverse group of undergraduates. Outreach to local schools and regional science museums, with talks and hands-on exercises on insect biology, laboratory visits by junior-high school students from underserved schools, and continuing participation and mentorship with the North Carolina Museum of Life and Science on the biology of insects are integral parts of the Principal Investigator's commitment to disseminating science and making the resources provided by NSF more broadly available to the local community.The proposed research has three principal aims: (1) to develop an improved theory and new equations for static allometry, (2) to test and validate the theory against rich and diverse data sets from insects and mammals, and (3) to investigate the physiological factors that give rise to allometric relationships. The experimental work will focus on wing-body allometry in Lepidoptera, where the control of growth and size is best understood. Growth and size are controlled by developmental hormones and by the timing and duration of hormone secretion. This work will use several genetic strains of Manduca sexta that differ in body size and that can be reared under different environmental conditions of temperature and nutrition, which also affect size and allometry. This will produce a rich data set that will permit a functional interpretation of the effects of genes and environment on growth patterns and on the resulting allometries. The results of this work will allow researchers to analyze the causes of complex non-linear allometries, and deduce the underlying growth patterns that give rise to those allometries. This work will also provide new insights into the physiological mechanisms by which variation in genetic background and environment alters size, shape and allometry.