Testing the genetic impact on the internal and external shape of teeth in non-human primates

牙齿提供有关物种的行为、饮食和健康的信息。由于这些独特的特征，牙科研究提供了许多关于过去人类和非人类灵长类(NHP)种群的信息。除了关于饮食、行为和健康的信息外，牙齿的外部形态(形状)在谱系进化和种群关联的研究中也得到了广泛的分析。这些研究基于这样一种观点，即牙齿发育和由此产生的牙齿形态受到强大的基因控制。然而，牙齿的形态变异很大，对于许多牙齿形态性状来说，强基因控制的假设仍然没有得到验证。这项研究在灵长类骨骼标本中使用非侵入性技术提高了关于外部和内部牙齿形态的知识。该项目支持处于不同阶段的学生和学者(博士后、研究生和本科生)，并包括针对波多黎各和纽约的K-12学生的外联活动。利用当地临床社区和阿肯色大学牙科预科项目之间的合作伙伴关系，该项目还通过为有抱负的牙医提供研究培训和职业发展机会，使社会受益。推断进化相关性的分析假设牙齿特征忠实地传递遗传谱系信息。但这一假设尚未在许多牙齿形态特征中得到实证检验。本研究测量了两种NHP(M.mulatta，S.fuscicollis；N=550)牙釉质外表面、釉质-牙本质交界处、牙根和牙髓腔的变化。使用配对的MicroCT和系谱数据，本项目采用数量遗传学的方法来回答以下问题：(1)牙齿形态变异(跨越不同的牙齿和组织)受基因的影响有多大？(2)在整个发育过程中，什么环境因素影响牙齿的形成？(3)牙齿特征在遗传上有多大程度的关联(受相同基因的影响)？以及(4)不同类群之间的牙齿遗传结构是否存在差异？通过生成新的遗传力、进化性和遗传相关性估计，该项目提供了对牙齿变异的驱动机制以及如何在整个发育过程中招募基因来影响不同的牙齿结构的见解。这些信息对于证实牙齿用于重建进化过程以及压力和疾病的经历是至关重要的。这项研究具有创新性，它结合了内部形态，使用了非破坏性技术，并详细检查了内部和外部牙齿形态发展的不同时刻。这项研究贡献了1,000多个头骨和牙齿的高分辨率扫描和3D表面模型，扩展了分析的骨骼收藏的管理，并通过开放获取的数字档案加强了教学和研究基础设施。该项目由生物人类学计划、既定的激励竞争研究计划(EPSCoR)和SBE博士后奖学金共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Teeth provide information about the behavior, diet and health of a species. Due to these unique characteristics, dental studies have provided much information about past human and non-human primate (NHP) populations. In addition to the information about diet, behavior and health, teeth’s external morphology (shape) has been extensively analyzed in studies of lineage evolution and population relatedness. These studies rest on the idea that tooth development and resulting tooth morphology are under strong genetic control. However, morphological variation of teeth is high, and for many dental morphological traits the assumption of strong genetic control remains untested. This study advances knowledge about external and internal tooth morphology using non-invasive techniques in primate skeletal collections. The project supports students and scholars at different stages (postdoctoral, graduate and undergraduate students), and includes outreach activities directed to K-12 students in Puerto Rico and New York. Leveraging partnerships between the local clinical community and the University of Arkansas’ Predental Studies Program, this project also benefits society by providing research training and professional development opportunities to aspiring dentists. Analyses that infer evolutionary relatedness assume that dental traits faithfully relay genetic lineage information. But this assumption has yet to be empirically tested in many dental morphological traits. This study measures variation at the outer enamel surface, enamel-dentine junction, root, and pulp chamber in two NHP (M. mulatta, S. fuscicollis; N=550). Using paired microCT and pedigree data, this project takes a quantitative genetic approach to answer the following questions: (1) To what degree is dental morphometric variation (across distinct teeth and tissues) influenced by genes?; (2) What environmental factors impact tooth form throughout development?; (3) To what degree are tooth characters genetically correlated (influenced by the same genes)?; and (4) Does dental genetic architecture differ across taxa? By generating novel heritability, evolvability, and genetic correlation estimates, this project provides insights into the driving mechanisms of dental variation and how genes are recruited throughout development to influence distinct tooth structures. This information is essential to ground truthing the use of teeth for reconstructing evolutionary processes and experiences of stress and illness. The study is innovative in its incorporation of internal morphology, the use of non-destructive techniques, and its detailed examination of distinct moments in the development of internal and external dental morphology. The study contributes over 1,000 high-resolution scans and 3D surface models of skulls and teeth, extending curation of analyzed skeletal collections and enhancing teaching and research infrastructure through open-access digital archives.This project is jointly funded by the Biological Anthropology Program, the Established Program to Stimulate Competitive Research (EPSCoR), and the SBE Postdoctoral Fellowships.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.