An experimental approach for determining gene function in which the sequence of a gene of unknown function is deliberately altered in vitro (q.v.) and introduced back into the cell or the organism, or the expression of the gene is disrupted in order to determine its phenotypic effect. Gene modification or knockout (q.v.) is achieved by such means as chemical and transposon-induced mutagenesis, gene targeting (q.v.), and RNA interference (RNAi) (q.v.). With the availability of tools for genome manipulation and whole-genome sequence data, reverse genetics has gained prominence in genetic analysis in a variety of organisms, including bacteria, yeast, the nematode, the fruit fly, the mouse, and many plant species. This approach is the reverse of the regular or forward genetics approach, in which one begins with a mutant allele or phenotype and then identifies the wild-type gene and its biological effect. See functional cloning, gene targeting, knockout, positional cloning, transgenic animals.
Subjects: Genetics and Genomics.