A change in the sequence of bases in DNA or RNA is called a Mutation. Does the word mutation make you think of science fiction and bug-eyed monsters? Think again. Everyone has Mutations. In fact, most people have dozens or even hundreds of mutations in their DNA. Mutations are essential for evolution to occur. They are the ultimate source of all new genetic material new alleles in a species. Although most mutations have no effect on the organisms in which they occur, some mutations are beneficial. Even harmful mutations rarely cause drastic changes in organisms.
