Directed mutagenesis using the polymerase chain reaction

The polymerase chain reaction (PCR) is most often used for the enzymatic amplification and direct sequencing of small quantities of nucleic acids. This technology can also be used as a quick and efficient method for introducing any desired sequence change into the DNA of interest. This unit contains two basic protocols for introducing base changes into specific DNA sequences. The first describes the incorporation of a restriction site and the second details the generation of specific point mutations. An alternate protocol describes generating point mutations by sequential PCR steps. Although the general procedure is the same in all three protocols, there are differences in the design of the synthetic oligonucleotide primers and in the subsequent cloning and analyses of the amplified fragments.