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The permissive temperature is the temperature at which a temperature-sensitive mutant gene product takes on a normal, functional phenotype. [2] When a temperature-sensitive mutant is grown in a permissive condition, the mutant gene product behaves normally (meaning that the phenotype is not observed), even if there is a mutant allele present.
One example of a conditional lethal is favism, a sex-linked inherited condition that causes the carrier to develop hemolytic anemia when they eat fava beans. [ 8 ] An infection of an E. coli host cell by a bacteriophage (phage) T4 temperature sensitive (ts) conditionally lethal mutant at a high restrictive temperature leads to lack of viable ...
Escherichia virus T4 is a species of bacteriophages that infect Escherichia coli bacteria. It is a double-stranded DNA virus in the subfamily Tevenvirinae of the family Straboviridae . T4 is capable of undergoing only a lytic life cycle and not the lysogenic life cycle .
One type of mutation in the T4 bacteriophage identified by researchers in phage genetics by the 1950s was known as r (for rapid), which caused the phage to destroy bacteria more quickly than normal. These could be spotted easily because they would produce larger plaques rather than the smaller plaques characteristic of the wild type virus.
Conditional mutation is a mutation that has wild-type (or less severe) phenotype under certain "permissive" environmental conditions and a mutant phenotype under certain "restrictive" conditions. For example, a temperature-sensitive mutation can cause cell death at high temperature (restrictive condition), but might have no deleterious ...
The isolation of conditional lethal mutants of phage during 1962-1964 by the phage group members provided an opportunity to study the function of virtually all of the genes that are essential for growth of the phage under laboratory conditions. [28] [29] One class of conditional lethal mutants is known as amber mutants. [30]
However, not all species are able to degrade mRNA fast enough to survive. One study found that in a temperature-sensitive strain of E. coli, there was a mutation that could be lethal: the RNA in this strain of E. coli degraded much slower than in other strains. The researchers who conducted this study exposed samples of the strain to different ...
The isolation of conditional lethal mutants of the bacterial virus T4 (bacteriophage T4) during 1962-1964 by members of the phage group at the California Institute of Technology provided an opportunity to study the function of virtually all of the genes that are essential for growth of the bacteriophage under laboratory conditions. [3]