Introduction

Although modern dental genetics had its roots in Aristotelian science, it really owes its origin to the work of Gregory Bateson and to the rediscovery in 1900 of Gregor Mendel's work. Bateson introduced the concept of teeth as serially repeated or meristic structures (Bateson, 1894) which, he suggested, should be viewed as a unit, varying and evolving as a whole. Bateson further characterised the properties of a meristic series as follows: first, members of a series show serial homology and hence differences between them should be seen as quantitative rather than qualitative; second, the form of each member of a series is dependent upon its position within the series as a whole. Three of Bateson's contemporaries, however, held opposing views, regarding units within the dentition as functional rather than morphogenetic. Scott (1892) suggested that the apparent serial homology between premolar and molar cusps was nothing more than the deceptive result of convergent evolution, a view which implied that each tooth was under independent hereditary control. Rutimeyer (1863) and Wortman (1886) suggested that all the teeth were in fact modified molars, with the implication that all the teeth shared the same hereditary determinants. It was when the importance of morphological variation began to be realised, toward the close of the nineteenth century, that questions concerning its causation began to be asked. The foremost question concerning inheritance asked during this period was whether the totality of characters was controlled by a single substance or by separate, independently varying particles.