Acquired mutation: A mutation (a genetic change) acquired by a somatic cell after conception. Acquired mutations occur in somatic cells, not germ cells, and so cannot be transmitted to the children. However, acquired mutations are transmitted to all cells descended from the mutant cell, giving rise to a clone (colony) of cells marked by the mutation. Some acquired mutations are involved in the development of cancer. Also known as an acquired genetic mutation, somatic mutation, or somatic cell mutation.