Doctoral Dissertation Research: Morphological integration between the face and dentition throughout ontogeny

面部和牙齿的大小和形状的差异经常被用来确定物种的亲缘关系。例如，与黑猩猩和我们早期的人类祖先相比，现代人的脸更平，嘴更宽，牙齿更小。尚不完全清楚的是，脸和牙齿是两个可以独立进化的独立单位，还是在进化过程中紧密相关。在这个项目中，研究人员将研究人类、黑猩猩和倭黑猩猩的面部和牙齿之间的形态整合，以测试在生长过程中面部大小和形状的特定变化是否与特定的牙齿发育事件有关，比如成年磨牙的形成或爆发。这个项目的发现将有助于我们对人类进化史的理解，并将为其他研究提供数据。研究结果更广泛地适用于正畸治疗和颅面外科手术的规划，也将支持少数民族本科生和研究生的培养。在这个为期两年的项目中，研究人员将使用医学计算机断层扫描（CT）和高分辨率微CT扫描，从现有的骨骼收藏中生成400多个人类、黑猩猩和倭黑猩猩的头骨和牙齿的三维虚拟模型。数据将通过三维地标和线性、角度和体积测量进行量化，然后将其分为牙齿发育的五个等级，以解决有关面部和牙列共变的具体假设。这些发现将与灵长类动物分类学、颅齿进化和个体发生有关，并可能对了解颅面疾病具有临床意义。本项目产生的microCT和CT数据将被汇编成一个开放访问的数据库，用于其他科学研究，从而增加对博物馆标本的虚拟访问，防止对脆弱的骨骼收藏品的进一步破坏。该项目还将促进生物人类学的多样性，因为共同负责人是一名少数民族女性研究生。

Differences in the size and shape of the face and teeth are often used to determine the relatedness of species. Modern humans, for example, have flatter faces, wider mouths and smaller teeth compared to chimpanzees and our early human ancestors. What is not fully understood is whether the face and teeth are two separate units that can evolve independently or if they are tightly correlated during evolution. In this project, the investigators will study morphological (shape) integration between the face and teeth in humans, chimpanzees and bonobos to test whether specific changes in the size and shape of the face during growth are associated with particular dental developmental events, such as the formation or eruption of the adult molars. The findings from this project will contribute to our understanding of the evolutionary history of humans, and data will be made available for other studies. The results are more broadly applicable for the planning of orthodontic treatments and craniofacial surgeries, and the project will also support minority undergraduate and graduate training. During this two-year project, the investigators will use medical computed tomography (CT) and high resolution microCT scans to generate three dimensional (3D) virtual models of the crania and teeth of over 400 humans, chimpanzees and bonobos from existing skeletal collections. Data will be quantified with 3D landmarks and linear, angular and volumetric measurements, and then binned into five grades of dental development to address specific hypotheses about covariation of the face and dentition. The findings will be relevant to primate systematics, craniodental evolution and ontogeny, and may have clinical implications for understanding craniofacial disorders. The microCT and CT data generated by this project will be compiled into an open-access database for other scientific research, thereby increasing virtual access to museum specimens and preventing further damage to fragile skeletal collections. The project will also promote diversity in biological anthropology, as the co-PI is a female, minority graduate student.