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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.
UV light can cause DNA damage that leads to mutations.
UV light can cause DNA damage that leads to mutations.