The origin of extra teeth in mammals

Abstract

The occurrence of extra teeth in mammals is reviewed. It is sug- gested that most of the extra teeth may be interpreted either (1) as the effect of additional creation and development of a tooth germ, caused by the influence of genes which are rare but still present in the gene pool of a given species and which occurred much more frequently in those of its ancestral species, or (2) as the effect of development of a supernumerary tooth germ originated as a result of complete splitting of a tooth germ, which may be inherited or due to a mutation or a disturbance or change in the genetic control of tooth development. Supporting evidence for this hypothesis is presented.