Main Page | See live article | Alphabetical index


This article is about the genetic phenomenon. For mutation in linguistic, see sandhi. For the 1998 indie rock album by Beck, see Mutations.

Mutations (or mutagenesis, both words originating in the Latin word mutare, to change) are permanent, transmissible changes to the genetic material (usually DNA or RNA) of an organism. Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses. Mutations often lead to the malfunction or death of a cell and can cause cancer in higher organisms. Mutations are considered the driving force of evolution, where less favorable mutations are removed by natural selection, but favorable ones tend to accumulate. Neutral mutations do not affect the organism and can accumulate over time, which might result in what is known as Punctuated Equilibrium; a modern variation on classic evolutionary theory.

Two classes of mutations are spontaneous mutations (often called background level) and induced mutations caused by mutagens.

basic types of mutations are:

Spontaneous mutations on the molecular level include: Induced mutations on the molecular level can be caused by: DNA has so-called hotspots, where mutations occur up to 100 times more frequently than the normal mutation rate. A hotspot can be at an unusual base, e.g., 5'-methylcytosine.

It should be noted that, science fiction to the contrary, the overwhelming majority of mutations have no real effect, and the majority of the rest are harmful, if not fatal.

See also: homeobox macromutation