Any change in the DNA sequence of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect.

What type of cell is a mutation?

Figure 2: Mutations can occur in germ-line cells or somatic cells. Germ-line mutations occur in reproductive cells (sperm or eggs) and are passed to an organism's offspring during sexual reproduction.

What is a mutation defined as?

Mutations. Definition. A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. A Mutagen is an agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed.