Genes and genotypes affecting the teeth of the mouse

ABSTRACT This paper is dedicated in gratitude and affection to Professor Hans Nachtsheim on the occasion of his seventy-fifth birthday (13th June 1965). 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. The fact that their interpretation in developmental terms is far from obvious may act as a stimulus to further work on the embryology of both the dental crown and the roots. The material to be described in this paper offers opportunities for such an approach not hitherto available.