Mutations

A mutation is a change that occurs in a gene or chromosome that can cause incorrect or different proteins to be made and alter an organism's normal trait.

A mutation in the DNA can occur when a single base pair is changed, removed, or added. Mutations can also happen when large sections of DNA are altered.

Other mutations happen when the chromosomes don't separate properly during meiosis. Sex cells can end up with more or less than the normal number of chromosomes.

Mutations are harmful if they decrease an organism's ability to survive or reproduce. Other mutations can be helpful. Mutations are often inherited and introduce changes in a species.