International Research Fellowship Program: Ontogenetic and Evolutionary Shape Variation and Modularity in the Mammalian Skull

[502186]戈斯瓦米国际研究奖学金计划使美国科学家和工程师能够到国外进行三到二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Anjali Goswami博士与Marcelo Sanchez-Villagra博士在英国伦敦自然古生物博物馆进行为期22个月的研究。发育通常被认为是形态变化的主要影响因素，形态变化为进化提供了原料。对这一假设的明确检验需要对发育形态进行量化，以测量其对成体变异的影响，但迄今为止，由于难以从切片组织学标本中获得测量结果，发育形态的量化一直受到阻碍。本研究采用新的成像和数字化软件，从切片材料中构建三维模型。利用这些模型，Goswami博士对哺乳动物颅骨的个体发生形状进行形态计量学分析，以检验发育对成年形态影响的基本假设。格斯瓦米博士之前的研究表明，成年哺乳动物的头骨被分成几个独立的部分或模块，这些部分或模块可以相互独立地变化。这些研究表明，在成人头骨中观察到的模块是由发育中的骨骼之间的相互作用产生和影响的。测量颅骨发育过程中形状和变异的变化，可以直接测试发育对成人颅骨形状的影响。这些个体发生数据随后被纳入计算机模拟，以模拟进化变化，以确定颅骨模块的发育差异如何在哺乳动物物种之间产生观察到的差异。这项研究提供了第一个跨越哺乳动物头骨复杂系统发展的比较形态测量数据集。本研究中发展的新方法和分析方法极大地扩展了目前胚胎学和形态计量学研究的范围。这个独特的数据集也将对许多其他研究有用，包括发育遗传学、缝合形成、进化速率和系统遗传学，以及为发育障碍的医学研究提供广泛的比较数据。

0502186GoswamiThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Anjali Goswami to work with Dr. Marcelo Sanchez-Villagra at the Natural Museum of Paleontology in London, UK.Development is often presented as a major influence on morphological variation, which provides the raw material for evolution. Explicit tests of this hypothesis require quantification of developmental shape to measure its influence on adult variation, but, thus far, quantification of developing morphology has been hindered by difficulties in obtaining measurements from sectioned histological specimens. This study adapts new imaging and digitizing software to construct 3-D models from sectioned material. With these models, Dr. Goswami conducts morphometric analysis of ontogenetic shape in the mammalian skull to test fundamental hypotheses on the influence of development on adult morphology. Previous work by Dr. Goswami has shown that the adult mammalian skull is divided into several independent components, or modules, that can vary independently of each other. Those studies suggested that the observed modules in the adult skull are created and influenced by interactions among developing bones. Measuring the changes in shape and variation during skull development allows for direct testing of the influence of development on adult skull shape. This ontogenetic data is then incorporated into computer simulations to model evolutionary change to determine how developmental differences in skull modules may create the observed differences across mammalian species.This study provides the first comparative morphometric dataset spanning the development of a complex system, the mammalian skull. The new methodologies and analyses developed in this study greatly expand the current scope of embryological and morphometric research. This unique dataset will also be useful for many other studies, spanning developmental genetics, suture formation, evolutionary rates, and phylogenetics, as well as providing extensive comparative data for medical research of developmental disorders.