MOLECULAR GENETIC INVESTIGATION OF TWINS, FAMILIES, AND POPULATIONS

Twins have long been of interest for illuminating genetic and environmental influences on human traits and diseases. These explorations have been accelerated by the substantial amount of information collected from twins and their families participating in twin registers around the world. I demonstrated that genotype data from Australian, Dutch, and Midwestern American twin-family populations can be reasonably combined for joint analysis. Genetic and phenotypic data acquired by twin registers provide insight into the role of genetics in human complex traits, such as birthweight. My results in a meta-analysis of eight twin cohorts indicate that the same genetic variants underly birthweight in twins and non-twins and that future genome-wide studies might benefit from including data from large twin registers. Applying a genetic association design to the twinning phenomenon will also aid in uncovering its biological and genetic underpinnings. Overall, important scientific and medical findings involve global populations of twins and their relatives.