Abstract
Random mutagenesis is a useful technique to study the functions of different gene products. Propagation of the genes cloned in plasmids through a mutator strain, like Escherichia coli XL1-red, produces randomly mutagenized plasmid libraries. This method offers a very simple and economic way of introducing random point mutations throughout the gene with a fairly high mutation rate. The whole process involves transformation and propagation of a plasmid containing the desired gene into the XL-1 red strain, isolating the mutagenized plasmid library and transforming this library into a desired strain for screening the mutant phenotype.