Complex dental phenotypes - inferences from family data

1. What proportion of a population’s phenotypic variation is due to genes, and what proportion is due to environmental factors?

2. How do genes and the environment interact to produce specific phenotypes, and how might such knowledge better inform clinical decision-making?

Methods:  These questions can be addressed using family studies; the former through use of population models of phenotypes that exhibit familial aggregation, and using linkage and association analyses to identify key genes; the latter by identifying functional variants and quantifying levels of gene expression.  The role of the epigenome in development and patterns of trait transmission has assumed increased importance in biological models of dental variation.  This, too, can be addressed through judicious use of family data.

Results:  This presentation will illustrate how studies of twin families can be used to partition population variation into genetic and environmental components using mathematical models of the twin relationship.  It will explore how such models can reveal information about relationships between dental features, and how these models can advantageously incorporate molecular marker data to identify genes of major influence.  Finally, the presentation will briefly examine how studies of monozygotic twins can be used to model the role of the epigenome in dental development.

Conclusions:  Family studies present a powerful, top-down approach to exploring variation in complex dental phenotypes.

Acknowledgements: We acknowledge the NHMRC, ADRF, Foundation for Children and Colgate for their support and we thank the twins and their families for their participation.