Reptilian tooth and jaw development

哺乳动物及其史前近亲的颌骨和牙齿的化石记录相当广泛，我们可以看到早期哺乳动物具有许多爬行动物的特征。然而，现代哺乳动物丧失这些特征的过程在基因水平上还没有得到很好的理解。由于缺乏关于爬行动物的发育或分子研究的信息，很难得到一个完整的进化图景。由于爬行动物很早就与哺乳动物分道扬镳，我们研究的目标是比较和对比哺乳动物、鸟类、蛇和海龟之间发育重要基因的DNA序列。我们的目标是了解可能导致特定适应的基因表达模式和基因功能的差异。在本研究计划中，将调查蛇不断更换牙齿的基础以及海龟为什么会失去牙齿。此外，还将研究高度专业化颌骨结构的发展。这将是关于蛇和龟胚胎面部发育的第一批信息。这些研究将大大增加我们对脊椎动物颌和牙齿如何进化的理解。

The fossil record for jaws and teeth of mammals and their prehistoric relatives is fairly extensive and we can see that early mammals had many reptilian characteristics. However the process by which present-day mammals lost some of these characters is not well understood at the gene level. The lack of information about reptiles from developmental or molecular studies makes it difficult to get a complete picture of evolution. Since reptiles diverged very early on from mammals the goal of our research is to compare and contrast DNA sequences of developmentally important genes amongst mammals, birds, snakes and turtles. Our aim is to appreciate the differences in gene expression patterns and gene function that may lead to specific adaptations. In this research proposal the basis for continuously replacing teeth in snakes and why turtles have lost their teeth will be investigated. In addition the development of the highly specialized jaw architecture will be studied. This will be some of the first information on snake and turtle embryonic facial development.  These studies will significantly increase our understanding of how vertebrate jaws and teeth evolved.