Reptilian tooth and jaw development

爬行动物牙齿和下巴的发育

• 批准号: 326908-2011
• 负责人: Richman, Joy
• 金额: $ 4.56万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=526739
• 关键词: Reptilian; tooth; jaw; development

This grant will study the formation of the teeth and jaws of reptiles. The first aim we will study the genes involved in replacement of teeth. Rodents are the most common model to study tooth development but their weakness is that they only have one set of teeth. To overcome this problem the proposed research use snakes and lizards that replace their teeth throughout life. In previous studies, we identified a network of signaling factors that control tooth initiation in pythons and geckos. Now we will add in two more signaling pathways and will expand our studies to later stages of tooth replacement. The importance of studying this question is that we will understand why some orders of animals have lost the ability to replace their teeth, while others form multiple sets. We will also address the contribution of 'stem cells' to tooth replacement. Our previous work suggested that putative stem cells are present in gecko teeth. Here we will activate these putative stem cells and follow their contributions to replacement teeth. The second aim of the grant will focus on skull development. Our preliminary studies have shown that the palates of snakes, lizards and birds are quite similar to mammals since they all pass through a similar intermediate stage. In contrast, turtles lack the transient structures called palatal shelves, yet the palatine bones still form and meet in the midline. The proposed experiments here will discover how the turtle palate is formed by taking a different developmental path. Finally we will be addressing the embryonic origins of the unique and ancient turtle skull shape. We will identify a group of genes that are different in the turtle versus the chicken and then we will test whether they are sufficient to make the bird skull more like that of the turtle. In summary, our application of current developmental biology techniques to reptiles will provide a wealth of new insights into evolution including why humans and other mammals are limited to 2 sets of teeth and whether or not turtles are the most primitive reptile order.

这笔赠款将研究爬行动物牙齿和颌骨的形成。第一个目标，我们将研究与牙齿替换有关的基因。啮齿动物是研究牙齿发育最常见的模型，但它们的弱点是只有一组牙齿。为了解决这个问题，这项拟议的研究使用了蛇和蜥蜴来替代它们的牙齿。在以前的研究中，我们发现了蟒蛇和壁虎中控制牙齿启动的信号因子网络。现在，我们将增加另外两个信号通路，并将我们的研究扩展到牙齿替换的后期阶段。研究这个问题的重要性在于，我们将理解为什么一些动物目失去了更换牙齿的能力，而另一些动物则形成了多个牙齿。我们还将讨论“干细胞”对牙齿替换的贡献。我们之前的工作表明，壁虎牙齿中存在假定的干细胞。在这里，我们将激活这些假定的干细胞，并跟踪它们对替换牙齿的贡献。这笔赠款的第二个目标将集中在头骨开发上。我们的初步研究表明，蛇、蜥蜴和鸟类的味觉与哺乳动物非常相似，因为它们都经历了类似的中间阶段。相比之下，海龟缺乏被称为腭架的暂时性结构，但腭骨仍然形成并在中线相遇。这里提出的实验将发现海龟的上颚是如何通过走一条不同的发育道路形成的。最后，我们将讲述独特而古老的海龟头骨形状的胚胎起源。我们将确定一组在海龟和鸡身上不同的基因，然后我们将测试它们是否足以使鸟类的头骨更像海龟的头骨。总之，我们将目前的发育生物学技术应用于爬行动物，将为进化提供丰富的新见解，包括为什么人类和其他哺乳动物被限制为两组牙齿，以及海龟是否是最原始的爬行动物目。