Are identical twins truly identical?

Source:  Are identical twins truly identical?    Tag:  punnett square history
Identical twins are very commonly identified as being identical in looks. What makes them so special? Unlike regular children, identical twins are born every 1 in 350 births. Identical twins are also fertilized as one egg that eventually separates into two separate babies from the same genetic information. Since identical twins are from one egg and one sperm with one set of identical information, one can assume that twins are identical in every way, but they are not.

In a study conducted at the University of Alabama, a geneticist and his coworkers studied and compared multiple sets of identical twins DNA. In the study, some of the identical twins DNA differed at various points along their genetic genome. The study concluded that in some cases one twin had a gene that coded for a disease while the other twin was free of the harmful disease. The study states that the changes in the DNA can occur while developing or it may be through mutations.

Overall, this article was very interesting. As a fraternal twin, my brother and I look and act completely different but we are not identical which has always been a reason of why we are that way. However, every identical twin I know are completely different in their attitudes, like my brother and I, and in some cases their looks vary slightly. This article answered my questions that have never been answered.

primary article:  http://www.scientificamerican.com/article/identical-twins-genes-are-not-identical/