- A mutation is a change in the sequence of bases in the genetic code. Sometimes, the changes in the code have no effect on the amino acid sequence so the protein shape is not affected. Others, however, such as the sickle-cell mutation in the gene that produces haemoglobin replace one amino acid in the chain with another.
- This will affect how the protein folds up and its shape, so affects the way it works.
- Sometimes, mutations may have no effect while they can also be harmful and rarely, beneficial to the organism. For example, some mutations in bacteria make them resistant to the effects of antibiotics. Therefore, bacteria with that mutation survive when the antibiotic is used but bacteria without it will die.
- Mutations can be caused by chemicals or ionising radiation