Doctoral Dissertation Research: Musculoskeletal Craniofacial Evolution and Developmental Plasticity

本博士论文研究项目探讨早期断奶对颅面复合体发育过程中肌肉和骨骼组织进化的影响。现代人类颅面复合体已经进化得更小，中脸更短，大脑呈球状，这些特征与饮食和咀嚼的变化有关。以前的研究在比较和化石材料中使用骨有方法上的局限性。在这里，最先进的成像方法的新组合被用来分析骨和软组织在颅面发育过程中的变化。这项研究有可能为早期生命发展的公共卫生研究提供信息。该项目促进学生在STEM方面的培训和指导，结果数据通过出版物、演讲和公开可用的成像数据库传播。该项目使用一个标准化的比较模型来检查早期断奶和典型断奶对肌肉骨骼颅面发育的影响。该项目的具体目的是表征(1)颅面平整化和(2)早期断奶对早期口腔运动技能发展阶段肌肉骨骼表现、整合和对称性的影响。先前的研究主要集中在骨骼组织的变化上，这主要是由于标准CT显示的内容和化石记录中保存的内容的限制。在这个项目中使用了一种新型的增强微计算机断层扫描（micro-CT）方法来分析骨骼、肌肉和软骨的个体发生系列。这种多层次的研究设计结合了进化、行为、形态学和功能理论，使我们能够更好地理解功能和组织相互作用对颅面复合体肌肉骨骼发育的影响。此外，该项目可以提高我们对高度可塑性生命早期颅面复合物形式-功能相互关系的理解，对人类进化过程中的行为适应和生长轨迹具有指导意义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This doctoral dissertation research project examines the effects of early weaning on the evolution of the muscles and skeletal tissue in the developing craniofacial complex. The modern human craniofacial complex has evolved to become smaller, with shorter midface and globular brain shape, characteristics linked to changes in diet and chewing. Previous investigations of this topic using bone in comparative and fossil materials have methodological limitations. Here, a novel combination of state-of-the-art imaging methods is used to analyze changes in bone and soft tissues during craniofacial development. The research has the potential to inform public health research on early life development. The project fosters student training and mentoring in STEM, and resulting data are disseminated through publications, presentations, and publicly available imaging databases. The project uses a gracilized comparative model to examine the influence of early and typical weaning on musculoskeletal craniofacial development. The specific aims of this project are to characterize the effects of (1) craniofacial gracilization and (2) early weaning on musculoskeletal performance, integration, and symmetry during the stages of oral motor skill development in early life. Previous research has focused on changes in skeletal tissue, primarily due to limitations in what is visible in a standard CT and what is preserved in the fossil record. A novel combination of contrast enhanced micro-computed tomography (micro-CT) methods is used in this project to analyze ontogenetic series of bone, muscle, and cartilage. This multilevel research design incorporates evolutionary, behavioral, morphological, and functional theories, allowing greater understanding of the impact of function and tissue interactions on the musculoskeletal development in the craniofacial complex. Furthermore, this project can improve our understanding of the form-function interrelationships in the craniofacial complex during highly plastic early life stages, with implications for behavioral adaptations and growth trajectories during human evolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.