Posted: May 22nd, 2023

Monozygotic twins experience an epigenetic drift between each another

They concluded that the age-related increase in methylation variation was generally related to the distinct environmental factors for which familial factors may play a more important role. In conclusion, sustained epigenetic differences arise from early adulthood to old age and contribute to an increasing epigenetic variation of MZ twins during aging (Talens et al., 2012)

It must be noted that discordance for numerous multifaceted diseases is not necessarily associated aging. Kaprio et al. (1992) studied the cumulative incidence, concordance rate, and heritability for diabetes mellitus in a nationwide cohort of 13,888 twin pairs of the same sex in Finland. They found that the concordance rate for Type 1 diabetes was higher among monozygotic than dizygotic in the first and second decades of life.

They concluded that heritability for Type 1 diabetes was greater than that for Type 2 where both genetic and environmental factors seemed to play a significant role. In a different study, Bergem et al. (1997) compared the relative importance of heredity and the environment in the development of Alzheimer’s disease and vascular dementia. They found that the concordance of Alzheimer’s disease could be as high as 83% at a later age.

Collectively, epigenetic changes are not restricted to the prenatal period. Monozygotic twins experience an epigenetic drift between each another with advancing age (Fraga et al., 2005). Differences in epigenetic modifications are influenced by decreasing amounts of time shared together and behavioral differences (Fraga et al., 2005). Additionally, MZ twins provide a unique model that explains how genetically identical twins exhibit differences. This model lends itself to future research that addresses the role of epigenetic modifications in the establishment of the phenotype (Petronis et al., 2003; Wong, Gottesman, and Petronis, 2005).