The genetic material in the nucleus of a cell is a chemical called DNA. DNA is a polymer, made of two strands that wind around each other in a double helix. It is packaged into structures called chromosomes.
A gene is a small section of DNA on a chromosome. Each gene codes for a particular sequence of amino acids, and that sequence makes a specific protein.
The genome of an organism is all of its genetic material. The whole human genome has now been studied. This matters for medicine because scientists can search for genes linked to different types of disease. It also helps them to understand and treat inherited disorders. The human genome can even be used to trace the migration of people in the past.
