Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
J Anat. 2012 Sep;221(3):195-208. doi: 10.1111/j.1469-7580.2012.01531.x. Epub 2012 Jul 11.
This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals.
本文描述了基础有鳞目动物 Paroedura picta 的牙齿发育。由于其生殖策略、发育模式和在爬行动物中的位置，这种壁虎是研究爬行动物发育的极佳模式生物。在这里，我们记录了在胚胎发育过程中非功能性（零代）和功能性牙齿代的牙齿模式和发育。我们跟踪了从启动到细胞分化和固着的牙齿发育过程，随着牙原基从芽、帽到钟形阶段的发育。非功能性（零代）牙齿的单一代的命运是可变的，一些牙齿从口腔中排出，而另一些则被纳入功能性骨骼和牙齿，或被吸收。命运似乎取决于口腔内的起始部位，第一批零代牙齿在牙蕾形成之前形成。我们在功能性牙齿的釉质上皮中发现了中间层的证据，并表明牙齿的双尖牙形状是由釉质的不对称沉积形成的，而不是像在哺乳动物中观察到的那样由内釉上皮折叠形成的。
