Mutant
From Wikipedia, the free encyclopedia
A mutant is an individual, organism, or new genetic character arising or resulting from an instance of mutation, which is a sudden structural change within the DNA of a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the wildtype. The natural occurrence of genetic mutations is integral to the process of evolution.
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[edit] Usage of the word 'mutant'
Although not all mutations have a noticeable phenotypic effect, the common usage of the word mutant is generally a pejorative term only used for noticeable mutations.[1] The scientific usage is broader, referring to any organism differing from the wild type. A more general term for mutant is sport, which includes individuals who vary from type due to mutation, as well as those that vary from type due to other reasons.
Developmental abnormalities caused by errors during morphogenesis are sometimes incorrectly referred to as mutants, but do not actually arise from mutation. In a developmental abnormality, the DNA of the organism is unchanged and the abnormality cannot be passed on to progeny. Examples would be conjoined twins, or the conjoined banana at right.
Examples of true mutants include:
- blue lobsters,[2]
- albinos[3]
- those with extra toes or fingers.[4]
- fruit flies with legs in place of antennas.[5]
[edit] Somatic mutation
Occasionally, a body cell in a healthy organism will acquire a mutation caused by a genetic error occurring during routine cell division, or by environmental damage such as ultraviolet light exposure. This is also known as a "somatic mutation", and cannot be passed to progeny. If the mutation affects a gene controlling the cell cycle, the affected cell may begin to divide uncontrollably, creating cancer.
[edit] Wild type
Wild type (sometimes written wildtype, wild-type or +) is the genetic term used in texts for the typical form of an organism, strain, gene, or characteristic as it was first observed in nature.[6][7] Wild type refers to the most common phenotype in the natural population; however this may, over a period of time, be replaced by a mutant form, which then becomes the new wildtype. The phenotype can be dominant or recessive. Naturally occurring mutant phenotypes play a role in evolution.
[edit] See also
- Mutant (fictional) for mutants in popular culture
[edit] References
- ^ mutant. (n.d.). The American Heritage Dictionary of the English Language, Fourth Edition. Retrieved March 05, 2008, from Dictionary.com website: http://dictionary.reference.com/browse/mutant
- ^ WESH NBC affiliate news report
- ^ Picture of Snowflake, a white ape
- ^ Polydactyly, pictured in cats
- ^ Memorial University of Newfoundland page with picture, paragraph about antennapedia mutant flies
- ^ Robinson Roy (1999), "Genetics for Cat Breeders and Veterinarians", Butterworth Heinemann, ISBN 0-7506-4069-3
- ^ http://helios.bto.ed.ac.uk/bto/glossary/tuvwxyz.htm
