Genes and genotypes affecting the teeth of the mouse

The teeth of mammals have been studied in great detail both by palaeontologists and by taxonomists who are interested in differences between species or higher systematic categories which are ultimately genetic in nature. By contrast, little is known about intra-specific genetic variability of the dentition. An invitation to participate in an ‘Institute for Advanced Education in Dental Research’ sponsored by the American College of Dentists provided an occasion to explore the situation in the laboratory and, presently, in the wild house mouse. The main results of this search are given in this paper. The extent of the intra-specific variance discovered may help systematists in assessing how much importance to attach to the differences they encounter; and it will be shown how easily one can be misled, in a limited sample, as to what is ‘normal’. Two characteristic dental syndromes to be described pose a new kind of problem to dental pathology.