A genetic mutation is a change in the DNA sequence of an organism. These changes can occur naturally during cell division or can be caused by environmental factors like radiation or chemicals. Mutations can affect a single DNA base pair or larger sections of a chromosome, leading to variations in traits. Some mutations are harmless, while others can lead to diseases or increase the risk of certain conditions. For example, a mutation in the BRCA1 gene is linked to a higher risk of breast cancer. Overall, genetic mutations play a crucial role in evolution and the diversity of life.