A mutation is defined as a change in the base pair or a deletion of a few base pairs that affects the function of a gene or an entire chromosome.
Mutations can occur naturally or it can also be induced. THree such ways are:
Mutations may arise at low frequency due to the chemical instability of purine and pyrimidine bases and the errors occurred during DNA replication.
Natural exposure to certain environmental factors, such as ultraviolet light and chemical carcinogens can also cause mutations.
Intake of high doses of chemical mutagens or exposing to ionizing radiation may also cause mutation to occur.