mutagenesis

Mutagenesis is the process of inducing genetic mutations in an organism or in DNA sequences, with the aim of understanding gene function, altering traits, or creating variants for study or exploitation. In laboratory settings, mutagenesis is performed intentionally, whereas natural mutational processes occur spontaneously at low frequency. Mutations can range from single-nucleotide changes to large insertions, deletions, or chromosomal rearrangements.

Two broad classes exist: random mutagenesis, which generates genetic diversity without a predefined target, and targeted mutagenesis, which introduces changes at specific sites. Random methods include chemical mutagens such as ethyl methanesulfonate and N-ethyl-N-nitrosourea, nitrosoguanidine, and physical mutagens like ultraviolet light and ionizing radiation. These approaches produce point mutations, small insertions or deletions, and larger rearrangements. Transposon mutagenesis inserts a mobile genetic element to disrupt genes. Error-prone PCR and mutator strains introduce mutations during DNA replication. Targeted mutagenesis uses techniques such as site-directed mutagenesis, oligonucleotide-directed mutagenesis, and genome-editing approaches including CRISPR-Cas systems, homologous recombination, and selection-based methods to introduce precise changes.

Applications include functional genomics to determine gene function, metabolic engineering and strain improvement in microbes, protein engineering by altering amino acids, and creation of model organisms for biomedical research. In practice, mutagenesis is paired with screening or selection to identify variants with desirable phenotypes.

Safety and ethics: work is governed by biosafety guidelines; mutagenesis may introduce off-target effects, and regulatory frameworks govern its use in organisms and products.