ETYM Latin mutatio, from mutare to change: cf. French mutation. Related to Mutable.
Change; Biology, sudden variation from type, due to change in genes. In biology, a change in the genes produced by a change in the DNA that makes up the hereditary material of all living organisms. Mutations, the raw material of evolution, result from mistakes during replication (copying) of DNA molecules. Only a few improve the organism's performance and are therefore favored by natural selection. Mutation rates are increased by certain chemicals and by radiation.
Common mutations include the omission or insertion of a base (one of the chemical subunits of dna); these are known as point mutations. Larger-scale mutations include removal of a whole segment of DNA or its inversion within the DNA strand. Not all mutations affect the organism, because there is a certain amount of redundancy in the genetic information. If a mutation is “translated” from DNA into the protein that makes up the organism’s structure, it may be in a nonfunctional part of the protein and thus have no detectable effect. This is known as a neutral mutation, and is of importance in molecular clock studies because such mutations tend to accumulate gradually as time passes. Some mutations do affect genes that control protein production or functional parts of protein, and most of these are lethal to the organism.
The process or event of mutating.
In music, an organ stop which produces a pitch other than the normal wavelength pitch (8 ft) or one related by octave (16 ft, 4 ft, 2 ft, or 1 ft). For example, a Quint stop (2 2/3 ft) produces a pitch an octave and a fifth higher than the depressed key (for example the C4 key sounds at G5).