Over 99% of all DNA sequences are identical among all people. The small percentage that is different helps make each person unique. Those small differences explain why some people have blue eyes and others have brown eyes. They explain why some people are colorblind while others can differentiate between turquoise and cerulean.
Genetic variation is important when it comes to research. In genetics, an important research goal is to improve human health. To develop treatments that will be effective in all patients, research must include people from a range of backgrounds. This will help to ensure that everyone benefits from discoveries.
Last reviewed and updated August 2019