Mutant

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This article concerns biological mutants; for fictional aspects see Mutant (fictional)

A mutant (also known to early geneticists as a "monster") 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 parental type. In an organism or individual, the new character or trait may or may not be trivial, may occasionally be beneficial, but will usually result in either a genetic disorder or have no phenotypic effect whatsoever. The natural occurrence of genetic mutations is integral to the process of evolution. A more general term for mutant is sport, which includes individual who vary from type due to mutation, as well as those who vary from type due to other reasons.

Occasionally, a body cell in a healthy organism may acquire a mutation caused by a genetic error occurring during routine cell division. This is also known as a "somatic mutation." Such an error may result in cancer.

Creatures with visibly obvious mutations are often regarded as objects of curiosity. Examples include rare blue lobsters.<ref>WESH NBC affiliate news report</ref> albinos of many species<ref>Picture of Snowflake, a white ape</ref><ref>Pictures of albino (and other) reptiles</ref> and animals with extra limbs.<ref>Polydactyly, pictured in cats</ref> A well-known mutation in fruit flies causes the flies to have legs in place of antennas.<ref>Memorial University of Newfoundland page with picture, paragraph about antennapedia mutant flies</ref> An American aquarium even displays a remarkable "double mutant" snake that is both albino and has two heads<ref>BBC news report World Aquarium in St. Louis auctioning its albino two-headed rat snake. (The snake did not fetch enough money and was ultimately not sold)].</ref>

Similarly striking human mutations also occur occasionally. People who are completely covered in a fur-like coat of hair are one example (see hypertrichosis). There are also cases of newborn babies having an extended tailbone or a sixth finger. Purely internal, less obvious mutations are more common; a small fraction of these cause serious medical conditions or death. (The ratio is probably under 1.5%, as only about 1.5% of the genome encodes protein genes)<ref name="IHSGC2001">International Human Genome Sequencing Consortium (2001). "Initial sequencing and analysis of the human genome.". Nature 409 (6822): 860-921. PMID 11237011. [1]</ref>

Scientists often create mutant animals to study development and disease. This may involve the use of a random genetic screen, a specific 'gene knockout' or transgenesis (the transfer of genetic material from one organism to another). Among the most famous knockout mouse models is the obese, leptin-deficient, ob/ob mouse.<ref>Knockout mice at Rockerfeller.edu.</ref>