Developmental mechanisms regulating tooth succession and accession in the house shrew (Suncus murinus)

哺乳动物的双齿型牙齿替换的特征是乳牙列被恒牙列单次替换。由于小鼠从不更换牙齿，因此本研究以家鼩（Suncus murinus）为模型，探讨牙齿的继承和加入对双齿替换的控制。齿胚的发育顺序表明，两个相邻的齿胚不是同时发育的，而是有一个恒定的时间差。我们认为，这种模式的牙齿继承和加入可以解释由一个顺序的抑制级联模型，其中启动的时间和牙齿发育的间隔是由抑制从发育前相邻的牙胚。

The diphyodont tooth replacement in mammals is characterized by a single replacement of a deciduous dentition by a permanent dentition. Because the mouse never replaces its teeth, this study used the house shrew, Suncus murinus, as a model to investigate the control of the diphyodont replacement by successions and accessions of teeth. The developmental sequence of tooth germs in the house shrew indicates that two adjacent tooth germs do not develop simultaneously, but with a constant time lag. We suggest that this mode of tooth succession and accession can be explained by a sequential inhibitory cascade model in which the timing of initiation and the spacing of tooth development are determined by the inhibition from developmentally preceding adjacent tooth germs.