In general, deoxyribonucleic acid, or DNA, is a very stable molecule. As it conveys genetic information from one generation to the next, errors rarely occur; however, they are not totally absent. Alterations in the DNA are called mutations. Mutations are not necessarily harmful to an organism. Some mutations go completely unnoticed, while others are the driving force behind evolution. However, some mutations are harmful; the root cause of many cancers, for example, is genetic mutation.

Mutations are divided into two categories: germline mutations and somatic mutations. Germline mutations can be passed from one generation to the next. The mutation occurs in the DNA of an egg or sperm cell. Any offspring resulting from the egg or sperm will inherit the mutation from the affected parent. Somatic mutations are mutations that occur in any cells other than egg or sperm cells. These mutations cannot be passed on to the...