Doctoral Dissertation Improvement: The Influence of development and homology on hominin molar morphological diversity

-获奖摘要#1341148博士论文改进：发育和同源性对人类磨牙形态多样性的影响牙齿特征经常用于人类(人类及其化石亲属)的物种诊断和系统发育重建。对牙齿的研究也在重建人类饮食以及现代人类群体之间的生物关系方面发挥了重要作用。然而，牙齿变异不仅是系统发育和功能相互作用的结果，也是控制牙齿形态发生的发育过程的结果。有趣的是，发育对原始人牙齿形态多样性的作用通常被忽视了。博士生Alejandra Ortiz(纽约大学)在Shara Bailey博士的指导下进行的研究将调查发育是如何塑造原始人牙齿形态的进化的。具体地说，这个项目将研究从大样本磨牙中提取的几个牙齿特征，以探索同源性的发育基础(定义为由于共同祖先而产生的相似性)，并确定我们家族成员的发育整合模式。通过检查性状的同源性和独立性，这种综合的方法将试图识别具有较高系统发育价的牙齿特征，并有助于解决人类学中长期存在的问题，即过去人类系统发生假说的模糊性。利用发育信息也将有助于未知人类标本的分类鉴定。高分辨率微型计算机断层扫描(MicroCT)将分别用于显示牙釉质-牙本质交界处和外部牙釉质表面的牙齿内表面和外表面。这项研究将在大约500颗磨牙上进行，这些磨牙分布在来自潘属、南方古猿属、拟人属和人属的许多物种中。数据将通过视觉评估、三维几何形态测量、直线和面积测量进行定性和定量分析。该项目将促进科学界的国际合作，并为本科生提供培训机会。对这一项目的支持将鼓励生物科学领域的多样性，因为合作者是科学界代表性不足群体中的一名女性。重要的是，该项目将有助于开发一个虚拟的微型CT扫描集合，它的使用将最大限度地减少数据收集错误，并限制对易碎化石材料的操纵。根据与参与博物馆的个别协议，这些微型CT扫描将向公众开放。此外，来自该项目的指标数据将在网上免费提供。由于与人类进化有关的问题具有广泛的公众兴趣，这项研究的结果将在学术会议上提出，并在技术和流行出版物上传播。该项目将寻求在多个研究领域之间建立联系，包括牙科人类学、古人类学、系统学和进化发育生物学。

------Award Abstract #1341148Doctoral Dissertation Improvement: The Influence of development and homology on hominin molar morphological diversityDental features are frequently used in species diagnoses and phylogenetic reconstructions of hominins (humans and their fossil relatives). The study of teeth has also played an important role in reconstructing hominin diets, as well as biological relationships among recent human populations. However, dental variation is the result of not only phylogenetic and functional interactions, but also the developmental processes controlling tooth morphogenesis. Interestingly, the role of development on the morphological diversity in the hominin dentitions has generally been overlooked. Research by doctoral candidate Alejandra Ortiz (New York University), under the supervision of Dr. Shara Bailey, will investigate how development has shaped the evolution of hominin tooth forms. Specifically, this project will examine several dental traits drawn from a large sample of molars in order to explore the developmental basis of homology (defined as similarity due to common ancestry) and determine patterns of developmental integration in members of our lineage. By examining trait homology and independence, this integrative approach will attempt to identify dental features of high phylogenetic valence and help solve the long-standing problem in anthropology associated with the ambiguity of past hominin phylogenetic hypotheses. The use of developmental information will also contribute to the taxonomic identification of unknown hominin specimens.High-resolution micro-computed tomography (microCT) will be used to visualize the internal and external surface of teeth at the enamel-dentine junction and outer enamel surface, respectively. This research will be undertaken in approximately 500 molars assigned to a number of species from the genera Pan, Australopithecus, Paranthropus and Homo. Data will be analyzed both qualitatively and quantitatively via visual assessments, three-dimensional geometric morphometrics, and linear and area measurements.This project will promote international collaboration within the scientific community and provide training opportunities for undergraduate students. Support for this project will encourage diversity within the biological sciences, as the co-PI is a female from an underrepresented group in science. Importantly, this project will contribute to the development of a virtual collection of microCT scans, the use of which will minimize data collection errors and limit the manipulation of fragile fossil material. These microCT scans will be available for public access according to individual agreements with participating museums. Furthermore, metric data derived from this project will be made freely available online. Since questions related to human evolution are of broad public interest, results of this study will be presented at academic conferences, as well as disseminated in technical and popular publications. This project will seek to create linkages among multiple fields of research, including dental anthropology, paleoanthropology, systematics and evolutionary developmental biology.