I Genetic Variation Program

Most of any one person's DNA, some 99.9 percent, is exactly the same as any other person's DNA. (Identical twins are the exception, with 100 percent similarity). Differences in the sequence of DNA among individuals are called genetic variation.

Genetic variation explains some of the differences among people, such as eye color and blood group. Genetic variation also plays a role in whether a person has a higher or lower risk for getting particular diseases. Single gene differences in individuals account for some traits and diseases, such as the ABO blood group, cystic fibrosis and sickle cell disease. More complex interrelationships among multiple genes and the environment are responsible for many common diseases, such as diabetes, cancer, stroke, Alzheimer's disease, Parkinson's disease, depression, alcoholism, heart disease, arthritis and asthma. The Genetic Variation program supports research on genetic variation and how it relates to diseases, responses to drugs and environmental factors.

To learn more about the Genetic Variation Program, visit http://www.genome.gov/10001551.