Effect of epigenetic differences in identical twins

Abstract

Monozygotic (MZ) twins are an ideal model for scientific research since many of the confounding factors associated with most human studies, such as DNA sequence and environment, can be eliminated. Although MZ twins are genetically identical, they typically display some level of phenotypic discordance. With the emergence of the study of epigenetics, scientists have hypothesized that differences in epigenetic marks may account for some phenotypic discordance in MZ twins. Comparative analysis of the epigenomes of MZ twins discordant for disease, including cancer, obesity, and diabetes, has led to the identification of epigenetic modifications, including changes in DNA methylation, histone marks, and differences in microRNA expression, that may contribute to the disease phenotype. Following identification of these changes, researchers are working to elucidate both the cause and the potential mechanism by which these modifications may lead to disease. Understanding how epigenetic modifications drive changes in phenotype using MZ twin studies may serve as a powerful tool in identifying new experimental opportunities in health and disease.