DNA (deoxyribonucleic acid) is the building block of genetic information that is found inside the centre (nucleus) of most body cells. DNA determines what features a person inherits from his or her parents, such as blood type, hair colour, eye colour, and other characteristics.
Chromosomes are parts of body cells that carry the DNA. The DNA of each chromosome is divided up into genes. Each person's DNA contains thousands of genes.
Changes (mutations) can occur in the DNA of genes or chromosomes. These changes may be harmless and undetectable. Or the changes may affect certain body processes or functions to cause genetic conditions, such as hemophilia, cystic fibrosis, or Down syndrome.
Medical Review:Adam Husney MD - Family Medicine & Kathleen Romito MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Siobhan M. Dolan MD, MPH - Reproductive Genetics