Doctoral Dissertation Improvement: Craniofacial Asymmetry, Morphological Integration, and Developmental Instability in the Human Skull

这个项目使用颅面不对称来识别人类头骨中发育完整的字符。 了解颅面变异的正常范围，以及变异范围的限制，是涉及人类头骨的研究的必要基础。 性格特征的发育整合限制了变异性，因为这些特征作为一个单一的单位一起生长、适应和进化。 这个项目将确定通过直接发展相互作用（发展“模块”）整合的字符，并测试他们是否在压力条件下保持整合。 区分在压力下保持一致的整合模式对于适应、进化变化和物种形成的研究至关重要，波动不对称性研究的最新进展为识别发育整合性状提供了一种创新的新方法。 波动不对称性被定义为个体样本中边间变异的随机模式。 由于形态波动不对称的随机性，两个字符的波动不对称显着的协变表明，字符的发展整合。 该项目包括三个独立但相关的研究。 首先，该方法将被应用于分析正常成人头骨，以测试预测从大量现有的文献整合在头骨。 其次，将使用来自颅缝过早融合的儿童和正常对照组的数据来测试在生物力学约束应力下的整合维持。 最后，维护系统压力下的整合测试使用的数据从两个考古样本的人类生活在不同的条件下，在逆境中。 对于每次分析，Co-PI将从每个颅骨上的生物学相关标志收集三维坐标。 波动的不对称性将使用这些坐标数据和已建立的形态测量方法进行量化。 将测试协变模式以识别发育整合性状。 项目资金允许联合规划员访问收藏骨骼的各种博物馆。 此外，将获得足够的材料来支持该项目和进一步的相关研究，推进这位女性Co-PI的科学事业。 该项目的成果将包括有关人类头骨发育的独特信息以及对压力适应性反应的限制。

This project uses craniofacial asymmetry to identify developmentally integrated characters in the human skull. Understanding the normal range of craniofacial variation, as well as limitations on the range of variation, is a necessary foundation for research involving the human skull. Developmental integration of character traits constrains variability, because these traits grow, adapt, and evolve together as a single unit. This project will identify characters that are integrated through direct developmental interactions (developmental "modules") and test whether they remain integrated under conditions of stress. Distinguishing patterns of integration that remain consistent under stress is critical for studies of adaptation, evolutionary change and speciation.Recent advances in the study of fluctuating asymmetry offer an innovative new method for identifying developmentally integrated characters. Fluctuating asymmetry has been defined as a random pattern of between-sides variation in a sample of individuals. Because of the random nature of morphological fluctuating asymmetry, significant covariation in the fluctuating asymmetry of two characters indicates that the characters are developmentally integrated. This project consists of three separate but related studies. First, the methodology will be applied to analysis of normal adult skulls to test predictions from substantial existing literature on integration in the skull. Second, the maintenance of integration under the stress of biomechanical constraint will be tested using data from children with prematurely fused cranial sutures and a normal control group. Finally, the maintenance of integration under systemic stress is tested using data from two archaeological samples of humans that lived under conditions differing in adversity. For each analysis, the Co-PI will collect three-dimensional coordinates from biologically relevant landmarks on each skull. Fluctuating asymmetry will be quantified using these coordinate data and established morphometric methods. Patterns of covariation will be tested to identify developmentally integrated characters. Project funding permits the Co-PI to visit various museums housing skeletal collections. In addition, adequate materials will be obtained to support this project and further related research, advancing the scientific career of this female Co-PI. Results of this project will include unique information about development of the human skull and constraints on adaptive responses to stress.