Identical+Twins+Not+As+Identical+As+Believed

[|Science Daily] February 20, 2008 Believe it or not, identical twins are not as identical as we believed. The question that was being asked is, “How can it be that one identical twin might develop Parkinson’s disease, for instance, but not the other?” In the past, the answer to this question was mainly environmental factors, but now recent studies have proven otherwise. Researchers have studied 19 identical twins and have found differences in copy number of variation in DNA. CNV (copy number variation) occurs when a set of coding variation letters are missing from the DNA, or when extra copies of DNA segments are created. Humans will receive one chromosome from each of their parents. Sometimes pieces of DNA are missing from a chromosome, or mutations can cause the production of three, four or more copies of a certain strand of DNA. Most of the time, the number of copies has no impact on the health or the development of someone. But in other cases, it could potentially be one of the factors in developing a disease. These studies have shown how people are not as alike as we would think, but that each and every person is different and has their own specific genes.

Frank Holecek March 14, 2010