mutation /(mū̇*tā"shŭn)/

mu·ta·tion

mutation

n.
  1. Change; alteration, either in form or qualities.
    The vicissitude or mutations in the superior globe are no fit matter for this present argument.
  2. Gradual definitely tending variation, such as may be observed in a group of organisms in the fossils of successive geological levels. (Biol.)
  3. As now employed (first by de Vries), a cellular process resulting in a sudden inheritable variation (the offspring differing from its parents in some well-marked character or characters) as distinguished from a gradual variation in which the new characters become fully developed only in the course of many generations. The occurrence of mutations, the selection of strains carrying mutations permitting enhanced survival under prevailing conditions, and the mechanism of hereditary of the characters so appearing, are well-established facts; whether and to what extent the mutation process has played the most important part in the evolution of the existing species and other groups of organisms is an unresolved question. (Biol.)
  4. a variant strain of an organism in which the hereditary variant property is caused by a mutation{3}. (Biol.)