A genetic mutation is a change in the DNA sequence of an organism. This alteration can happen naturally during cell division or due to environmental factors like radiation or chemicals. Mutations can affect a single gene or larger sections of DNA, leading to variations in traits. Some mutations are harmless, while others can cause diseases or increase the risk of certain conditions. Mutations play a crucial role in evolution by introducing new traits into a population. For example, Darwin's theory of evolution suggests that beneficial mutations can help organisms adapt to their environment, leading to the survival of the fittest.