Identical twins may be more different from each other than that can be perceived. The primary similarities they have may be lost over the time that can leave them very different form each other.
Researchers have reported that this difference in identical twins is the direct result of their epigenome. Epigenome is the modifications that happen in the gene, not because of its genetic structure, but because of the varied expressions of the gene's DNA. Epigenome can affect the attributes in the twins that make them identical.
Scientists from Ohio State University, who had conducted the study, had said that the epigenetic effect can alter the genetic expressions in twins through varied exposure of chemicals, dietary habits and environmental factors can bring so much difference in the physiology of the twins that even cancer can occur in one and not in another.
Researchers had looked into the blood test samples of 40 pairs of twins, along with their health records and had found that the genetic similarities in gene expressions were most for the youngest pair of twins who were of 3 yrs age. These similarities were the least in the oldest pair of identical twin siblings who were 74 yrs of age. The results of the study showed that the epigenetic effect is least when young and increases with age, as the identical twins grow older.
Reference: Proceedings of the National Academy of Sciences, July 2005