Investigating the Effects of Enamel Growth Variables on Linear Enamel Hypoplasia in Primates

研究牙釉质生长变量对灵长类动物线性牙釉质发育不全的影响

• 批准号: 0607520
• 负责人: Debbie Guatelli-Steinberg
• 金额: $ 8.63万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0607520&HistoricalAwards=false
• 关键词: Investigating; Effects; Enamel; Growth; Variables

Linear enamel hypoplasia (LEH) is a defect of tooth enamel that reflects periods of nutritional or disease stress experienced during the early years of life, when teeth are forming. These defects form when such physiological stresses disrupt normal enamel growth, causing the formation of linear groves on the enamel surface. There are consistent differences among both extinct and living primate species in the frequency with which they exhibit these enamel defects. Of the great apes, bonobos have the highest frequencies of LEH. Chimpanzees and orangutans exhibit higher frequencies than gorillas, and lowland gorillas exhibit higher frequencies than mountain gorillas. Among human ancestors, Australopithecus has higher frequencies of multiple defects than Paranthropus, and Neanderthals exhibit LEH frequencies higher than some modern human groups but not others. Researchers usually assume that these LEH frequency differences among species are a direct reflection of differences in stress experience. However, species also differ in the way that their enamel grows. It is highly likely that species-specific differences in aspects of enamel growth are influencing the patterns that have been observed in the distribution of LEH in primates. Recent studies in modern humans have demonstrated that aspects of enamel growth affect how teeth record physiological stresses. Specifically, the percentage of the tooth crown composed of imbricational enamel (enamel covered by perikymata, external manifestations of internal growth increments known as striae of Retzius) affects the opportunity for defects to form, while the depth of perikymata affects defect perceptibility. This study represents the first systematic investigation of the extent to which these enamel growth variables can account for differences in LEH prevalence across primate species. The intellectual merit of this study lies in the insight it will provide into how the structure of enamel constrains defect formation across species. By understanding these constraints, clearer interpretations of what linear enamel hypoplasias reveal about physiological stress in fossil and living primates, including humans, will be possible. To answer the question of how enamel growth variables affect LEH prevalence across species, this study examines both internal (striae of Retzius) and external (perikymata) enamel growth structures across 70 primates species. Broader impacts include the creation of a large replica sample of primate dental specimens selected for the preservation of perikymata on their surfaces. Because perikymata provide a record of enamel growth, they can be used in additional studies of primate growth and development. This sample will be become part of the Menegaz-Bock dental cast collection housed in the Bioarchaeology Laboratory at The Ohio State University and will be made available to other researchers. Thus, this project will have a positive impact on the infrastructure of research in physical anthropology. The PI has used raw data from previous research in lab exercises in both graduate and undergraduate classes; data generated from this research will be used in this way as well. Finally, dental anthropology is a field in which female scientists have been traditionally underrepresented. The post-doctoral collaborator on this project is a female scientist, and this project will support her professional development.

线性牙釉质发育不全（LEH）是牙齿牙釉质的缺陷，它反映了在牙齿形成的早期生命中经历的营养或疾病压力时期。当这种生理应力破坏正常牙釉质生长时，这些缺陷形成，导致牙釉质表面线性树林的形成。在灭绝和活着的灵长类动物中，它们表现出这些搪瓷缺陷的频率都存在一致的差异。在大猿类中，Bonobos的频率最高。黑猩猩和猩猩的频率比大猩猩更高，低地大猩猩的频率高于山大猩猩。在人类祖先中，澳大利亚河的多种缺陷的频率高于丙二烷，尼安德特人的频率比某些现代人类群体高，但没有其他人。研究人员通常认为，物种之间的LEH频率差异直接反映了压力体验的差异。但是，物种在牙釉质生长的方式上也有所不同。在牙釉质生长方面的物种特异性差异很可能会影响灵长类动物中LEH分布中观察到的模式。对现代人类的最新研究表明，牙釉质生长的各个方面会影响牙齿记录生理压力的方式。具体而言，由牙胶牙齿组成的牙冠的百分比（牙釉质被植木覆盖，外部生长增量的外部表现称为retzius的曲线）会影响缺陷形成缺陷的机会，而Perikymata的深度则影响缺陷。这项研究代表了这些牙釉质生长变量可以解释灵长类动物的LEH患病率差异的程度的首次系统研究。这项研究的智力优点在于它将为搪瓷结构限制跨物种的缺陷形成的见解。通过理解这些约束，可以更清楚地解释牙釉质呼吸症对化石和活体灵长类动物（包括人类）的生理压力的揭示。为了回答牙釉质生长变量如何影响各种物种的LEH患病率的问题，本研究研究了70种灵长类动物物种的内部（retzius）和外部（Perikymata）牙釉质生长结构。更广泛的影响包括创建大量的灵长类动物牙齿样本样本，以保存其表面上的植物植物。由于Perikymata提供了搪瓷生长的记录，因此可以将它们用于灵长类动物生长和发育的其他研究。该样本将成为俄亥俄州立大学生物考古学实验室中安装的Menegaz-Bock牙科铸造系列的一部分，并将提供给其他研究人员。因此，该项目将对物理人类学研究基础设施产生积极影响。 PI在研究生和本科班级的实验室练习中使用了先前研究的原始数据；这项研究产生的数据也将以这种方式使用。最后，牙科人类学是一个传统上代表性不足的女性科学家的领域。该项目的博士后合作者是一位女科学家，该项目将支持她的专业发展。