Introduction and Aim A mutation is a change in the DNA of an organism. Mutations happen very oft en, and are mostly repaired by sophisticated cellular mechanisms. If a mutation is not properly repaired the resulting change in the DNA does not have any eff ect on the individual or its off spring in the vast majority of cases; occasionally the changed DNA may have a negative or positive consequence. However, the word ‘mutation’, and even more so the word ‘mutant’, carry highly negative connotations. Why is that? Mutations can indeed cause disease, but mutations are also one of the driving forces of evolution.