Investigating Genetic Mechanisms of the Baboon Dentition

对灵长类牙齿的研究有许多原因，从系统发育重建到牙齿发育再到功能形态。由于牙齿的组成，牙齿是灵长类化石中保存最频繁的部分，也是唯一已知的一些已灭绝的类群。牙齿适应了许多功能--例如咀嚼、准备食物和社会互动--但也包含了它们生长的记录，这一切都意味着可以从它们的化石形式中学到很多东西。从发育和进化的角度来看，牙齿也很重要。一旦长出牙齿，只有磨损、破裂和龋齿才会改变灵长类牙齿的形态，而且这些过程的影响很容易识别。因此，与骨骼相比，牙齿受环境和行为的影响相对较小。因此，牙齿对其变异的非遗传成分减少，更容易确定潜在的遗传机制。结合牙齿的所有这些特征，牙列是研究复杂表型遗传进化史的主要候选者。该项目建议使用狒狒模型对灵长类牙齿的遗传进化史进行研究。这个项目是数量遗传学和古生物学这两个通常截然不同的领域的一次新的整合，目的是为了研究和识别进化上显著的形态变异背后的遗传机制。该项目确定了非洲过去500万年狒狒进化过程中的牙齿特征，这些特征在德克萨斯州圣安东尼奥西南生物医学研究基金会的现代稀树草原狒狒血统群体中也存在差异。然后，将使用现代定量遗传分析来研究这种变异，以确定现代狒狒这种变异背后的遗传机制，因此，可能代表了决定过去狒狒物种这种变异的相同机制。这个项目代表着一个独特的机会，可以将现代遗传学的力量与化石记录的时间深度结合起来，同时研究基因组和解剖学，而不是作为独立的实体。这项研究的结果对进化和发育生物学以及人类学和灵长类动物学都有广泛的影响。这项研究将深入了解狒狒牙齿发育和图案形成的遗传机制，这些机制可能涉及包括人类及其祖先在内的其他灵长类动物的牙齿进化。因此，这项研究的结果将立即适用于人类牙齿进化的研究，以及许多其他灵长类动物的进化。

The primate dentition has been studied for many reasons ranging from phylogenetic reconstruction to dental development to functional morphology. Because of their composition, teeth are the most frequently preserved parts of fossil primates and the only ones known for some extinct taxa. Teeth are adapted for many functions - e.g. mastication, food preparation, and social interactions - but also contain a record of their growth, which all means that a great deal can be learned from their fossilized forms. The dentition is also important from the developmental and evolutionary perspective. Only wear, breakage and caries alter the morphology of primate teeth once eruption has occurred, and the effects of these processes are fairly easy to identify. Teeth are thus relatively less affected by environment and behavior than are bones. Consequently, teeth have a reduced nongenetic component to their variation and are more tractable for determining underlying genetic mechanisms. Combining all these characteristics of teeth, the dentition is a prime candidate for investigating the genetic evolutionary history of a complex phenotype. This project proposes research into the genetic evolutionary history of the primate dentition using a baboon model. This project is a novel integration of the usually disparate fields of quantitative genetics and paleontology in order to investigate and identify the genetic mechanisms underlying evolutionarily significant morphological variation. This project identifies dental traits from the last five million years of baboon evolution in Africa that also vary in a genotyped pedigreed colony of modern savanna baboons at the Southwest Foundation for Biomedical Research in San Antonio, Texas. This variation will then be studied using modern quantitative genetic analyses to identify the genetic mechanisms that underlie this variation in modern baboons, and thereby, probably represent the same mechanisms that determined this variation in past baboon species. This project represents a unique opportunity to integrate the power of modern genetics with the time depth of the fossil record to investigate the genome and anatomy simultaneously, rather than as separate entities. Results from this study have broad implications for evolutionary and developmental biology, as well as for anthropology and primatology. This study will provide insight into the genetic mechanisms that underlie tooth development and patterning in baboons, mechanisms likely to be involved in the evolution of teeth of other primates, including humans and their ancestors. Thus, the results of this study will be immediately applicable to the study of human dental evolution, as well as the evolution of many other primates.