mu·ta·tion /mjuˈteʃən/
 變化,轉變,母音變化


 mu·ta·tion /mjuˈteʃən/ 名詞
 突變,變異


 mu·ta·tion n.  Change; alteration, either in form or qualities.
    The vicissitude or mutations in the superior globe are no fit matter for this present argument.   --Bacon.
 2. Biol. Gradual definitely tending variation, such as may be observed in a group of organisms in the fossils of successive geological levels.
 3.  Biol. (a) 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. (b) The result of the above process; a suddenly produced variation.
 Note: Mutations can occur by a change in the fundamental coding sequence of the hereditary material, which in most organisms is DNA, but in some viruses is RNA.  It can also occur by rearrangement of an organism's chromosomes.  Specific mutations due to a change in DNA sequence have been recognized as causing certain specific hereditary diseases.  Certain processes which produce variation in the genotype of an organism, such as sexual mixing of chromosomes in offspring, or artificially induced recombination or introduction of novel genetic material into an organism, are not referred to as mutation.
 4. Biol. a variant strain of an organism in which the hereditary variant property is caused by a mutation3.

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 mutation
      n 1: (biology) an organism that has characteristics resulting
           from chromosomal alteration [syn: mutant, variation,
            sport]
      2: (genetics) any event that changes genetic structure; any
         alteration in the inherited nucleic acid sequence of the
         genotype of an organism [syn: genetic mutation, {chromosomal
         mutation]
      3: a change or alteration in form or qualities