What is a genetic mutation?
A genetic mutation is a change in the nucleotide sequence of DNA.
Most mutations only affect a single gene. This will affect a single protein.
Most genetic mutations will not be noticeable. However, mutations can produce an organism with a new phenotype. This phenotype may be advantageous or disadvantageous to an individual. As a result, mutations are controlled by natural selection.
A mutant gene that increases survival will spread throughout the population.
Sickle cell anaemia is a blood disorder. It is caused by an inherited mutation in the haemoglobin gene used by red blood cells.
Environmental factors can increase the rate of mutations in cells:
- Radiation: X-rays and ionising radiation can cause cells to mutate.
- Carcinogens: chemicals such as the tar in cigarettes can increase the mutation rate.