The Brisbane Adolescent Twin Study: Outline of study methods and research projects

An ongoing program at the Queensland Institute of Medical Research (QIMR) uses a resource of adolescent twins (2720 individuals) and their singleton siblings (1179), constituting 1324 families. A large number (4 500 families) have participated in two main studies (the mole and the cognition studies) with the aim of identifying genetic polymorphisms associated with moliness and cognitive function respectively, as well as several other projects that run in parallel with these studies. Most recently 950 families were invited to participate in a mail and phone study assessing reading ability, taste and smell sensitivity, and health and wellbeing. Although the program measures a broad range of phenotypes, the common focus of all studies is to reveal the genetic architecture underlying the trait, and thereby facilitate the search for quantitative trait loci. The present paper provides an overview of the studies, and highlights the significance of the resource, as well as some of the unique aspects of twin research. Twin studies have been used for centuries to investigate the heritability of a particular trait, and provide a method for investigating and partitioning the relative contributions of genes and the environ-ment to phenotypic variability in all human traits