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，今天的哺乳动物失去这些特征的过程在基因水平上还没有被很好地理解。由于缺乏来自发育或分子研究的爬行动物信息，因此很难获得进化的完整图景。由于爬行动物很早就从哺乳动物中分化出来，我们研究的目标是比较哺乳动物、鸟类、蛇和海龟中发育重要基因的DNA序列。我们的目的是了解基因表达模式和基因功能的差异，这些差异可能导致特定的适应。在这项研究提案中，将调查蛇不断更换牙齿的基础，以及海龟失去牙齿的原因。此外，还将研究高度专业化的颌骨建筑的发展。这将是有关蛇和海龟胚胎面部发育的一些首批信息。这些研究将显著增加我们对脊椎动物颌骨和牙齿进化的理解。

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.