DNA (deoxyribonucleic acid) is a substance containing genetic
information that is found inside the center (nucleus) of most body cells. DNA determines
what features a person inherits from his or her parents, such as blood type,
hair color, eye color, 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 tens of 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