3.34 Causes of mutation

Key Points:
1. Mutation is a change in the base sequence of the gene. New alleles are produced.
2. An example of what causes this is radiation, or ionising radiation like x-rays or sunlight which cause skin cancer.
3. A second example is chemicals, such as tar in tobacco changing the base sequence of the gene. Chemicals which do this are called mutagens. Carcinagens are mutagens which also cause cancer.