Molecular Biology Review

A study was recently conducted on what makes twins different. Some identical twins have small physical difference or tend to be more susceptible to disease than their pair. The theory for why these differences occur, as addressed in this article, is that chemical triggers switch on and off genes. They do this by attaching to the chromosome "like charms on a charm bracelet". This is called epigenetic modification. These chemicals come from virtual all around us in the environment. They affect genes differently depending on the chemical. Methyl groups, for instance, turn genes off where as acetyl groups turn genes on.

The study conducted examined 80 pairs of twins from three countries in Europe, who varied between the ages of 3-74. The study revealed fewer epigenetic differences in younger twins. Older twins and twins raised apart presented more differences. The conclusion of the study was that environmental changes such as whether the person is exposed to tobacco smoke, eats certain foods, or suffered some sort of emotional trauma, affects which genes are turned off or on.

This article caught my attention first because I had once seen a medical program on differences in identical twins and second because of my interest in genetics. I was very impressed by the study. I also find it very convincing. It is one a very few studies I have seen that really explain what may be going on with the twins. It seems to fit the issue very well and explain it on a highly logical basis. I look forward to any further study into this theory.