A mutation is a permanent change in the DNA sequence of a gene. This change can alter the genetic message carried by that gene, which can result in a change in the organism's characteristics.
Mutations can occur spontaneously during DNA replication or can be induced by external factors such as radiation, chemicals, or certain viruses.
The effects of mutations can vary widely depending on the type and location of the mutation. Some mutations may have no effect, while others can lead to genetic disorders, cancer, or changes in the organism's traits.