Uses of twins in studying the genetics of complex traits

Abstract

Twins provide a useful and powerful tool for identifying genes, by acting as ideally matched sib-pairs, but are also uniquely placed to measure the extent of their action, their expression and the nature of their interaction with the environment. Classical twin studies have provided insight into the relative genetic and environmental contribution to characteristics and diseases in human populations. The search for a more detailed understanding of genetic mechanisms through linkage and association has, however, traditionally been regarded as the province of other family designs. The last few years have seen a resurgence of interest in twin research following an increasing awareness that the study of twins can also provide an important contribution to localizing and understanding the function of specific genes.1 In this brief overview, we focus on these newer developments that are currently being applied in the search to uncover the genetic basis of disease.