Site-directed mutagenesis

Site-directed mutagenesis is a molecular biology method that is used to make specific and intentional mutations to a particular DNA sequence, such as a gene, or to its gene products. Also called site-specific mutagenesis or oligonucleotide-directed mutagenesis, it is widely used for investigating the structure and biological activity of DNA, RNA, and protein molecules, and for protein engineering. The term encompasses numerous techniques that work by a wide variety of distinct mechanisms, all with the same goal of creating one or more precise, targeted nucleotide mutations (either insertions, deletions, or substitutions) within a specific nucleic acid sequence.

Site-directed mutagenesis remains one of the most important laboratory methods for creating DNA libraries by introducing mutations into DNA sequences, but with decreasing costs of de novooligonucleotide synthesis, artificial gene synthesis has become an increasingly common alternative to mutating existing DNA sequences. New techniques for achieving site-directed mutagenesis continue to be developed. For example, the development of CRISPR/Cas9 technologies, based on a prokaryotic viral defense system, has allowed for precisely targeted in vivo, which is sometimes considered a type of site-directed mutagenesis.