mutant

1. A phenotype in which a mutation is manifested. 2. A gene that is rare and usually harmful, in contrast to a wild-type gene, not necessarily generated recently.

- active m. a m. with overt phenotypic expression.

- amber m. a m. with a mutation resulting in a UAG codon.

- auxotrophic m. m. with a nutritional requirement not present in the wild-type organism. SYN: defective organism, deficiency m..

- cold-sensitive m. a m. that is defective at low temperature but functional at normal temperature. Cf.:temperature-sensitive m..

- conditional-lethal m. SYN: conditionally lethal m..

- conditionally lethal m. a viral m. that can replicate under some (permissive) conditions but not under other (restrictive or nonpermissive) conditions, the parent (wild-type) strain being able to replicate under both conditions. See suppressor-sensitive m., temperature-sensitive m.. SYN: conditional-lethal m..

- deficiency m. SYN: auxotrophic m..

- inactive m. a m. that is not phenotypically manifest. SYN: silent m..

- petite m. a m. with a mutation that caused the microorganism to grow very slowly or to form small colonies. [Fr. small]

- quick-stop m. a bacterial m. that ceases replication immediately when the temperature reaches a certain level. Cf.:temperature-sensitive m..

- silent m. SYN: inactive m..

- suppressor-sensitive m. a conditionally lethal, host range, bacteriophage m. that produces nonsense codons and can replicate only in a host bacterium able to translate the nonsense codon; the mutation's effects are lethal ( i.e., prevent replication of the virus) in a bacterium without such a suppressor mechanism.

- temperature-sensitive m. a viral m. that is able to replicate at one portion of a temperature range but not at another, the parent (wild-type) strain being able to replicate over the whole temperature range; usually a product is not made at the elevated temperature. Cf.:cold-sensitive m., quick-stop m..

- uninducible m. a m. that cannot be induced.

- virulent phage m. a m. of a phage that is unable to establish lysogeny.

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mu·tant 'myüt-ənt adj of, relating to, or produced by mutation

mutant n a mutant individual

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n.

1. an individual in which a mutation has occurred, especially when the effect of the mutation is visible.

2. a characteristic showing the effects of a mutation.

• mutant adj.

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mu·tant (muґtənt) [L. mutare to change] 1. something, as an organism, cell, virus, or gene, that has undergone genetic mutation. 2. produced by mutation.