A screen (sometimes described as a "negative selection") for mutants that fail to survive under certain growth conditions. This approach has been widely used to identify mutants that fail to survive during infection of animals, but it can be applied to essentially any environmental condition.
A method for high-resolution mapping of the functional organization of a cloned gene. An in vitro transposition reaction is used to generate a large pool of insertion mutants in a defined region of DNA. DNA is isolated from the mutant pool before and after some genetic selection. The presence or absence of individual mutants at particular sites in each population is determined by PCR analysis and the PCR products are then separated by gel electrophoresis. Each different mutant will produce a distinct PCR product. If a PCR product is present in the "pre-selection" population, but absent from the "post-selection" population, insertions at that particular site may be essential for growth under the selective conditions. (This approach was developed by Singh, Crowley, and Brown (1997) Proc. Natl. Acad. Sci. USA 94: 1304-1309).
This is a type of genetic footprinting developed for identification of virulence genes in bacteria. Note the clever name -- the definition of gambit is: (i) An opening in which a minor piece is sacrificed to obtain a strategic advantage. (ii) A maneuver used to secure an advantage. (iii) A remark used to open or redirect a conversation. [From Spanish gambito, from Italian gambetto (the act of tripping someone), from gamba (leg).]
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Last modified July 5, 2004