Search results
Results from the WOW.Com Content Network
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 conditional gene knockout method is often used to model human diseases in other mammals. [2] It has increased scientists’ ability to study diseases, such as cancer, that develop in specific cell types or developmental stages. [4] It is known that mutations in the BRCA1 gene are linked to breast cancer.
A conditional gene knockout allows gene deletion in a tissue in a tissue specific manner. This is required in place of a gene knockout if the null mutation would lead to embryonic death, [13] or a specific tissue or cell type is of specific interest. This is done by introducing short sequences called loxP sites around the gene.
Conditional/inducible mutation approaches are then required that first allow the mouse to develop and mature normally prior to ablation of the gene of interest. Another serious limitation is a lack of evolutive adaptations in knockout model that might occur in wild type animals after they naturally mutate.
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 ...
There are several methods, or forms, of mutation that exist including spontaneous mutation, errors during replication and repair, as well as mutation due to environmental effects. [8] These origins of mutations can cause many different types of mutations which influence gene expression on both large and small scales.
Conditional mutations can be produced in mice which affect only specific cells or tissues at specific times, so that the mouse can develop to adulthood and the adult phenotype can be studied. In one case, MED1 was found to participate in controlling the timing of events of meiosis in male mice. [ 39 ]
This approach involves targeting a specific gene with a mutation and then observing what phenotype develops. [12] The mutation can be designed to inactivate the gene or only allow it to become active under certain conditions. Conditional mutations are useful for identifying genes that are normally lethal if non-functional. [13]