CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a powerful and precise gene-editing technology that enables scientists to alter DNA sequences and modify gene function. It is based on a natural defense system found in bacteria and archaea. The most commonly used system is CRISPR-Cas9, which uses a guide RNA (gRNA) to direct the Cas9 enzyme to a specific sequence of DNA. The Cas9 enzyme then acts like a pair of 'molecular scissors' to cut the DNA, allowing scientists to inactivate a gene, or to insert or correct a piece of DNA.
The CRISPR sequences were first observed in E. coli by Yoshizumi Ishino in 1987, but their biological function as an adaptive immune system in bacteria was not fully understood until the mid-2000s through the work of researchers like Francisco Mojica. The breakthrough for its use as a gene-editing tool came in 2012, when a seminal paper by Jennifer Doudna and Emmanuelle Charpentier demonstrated how the CRISPR-Cas9 system could be programmed to cut any DNA sequence. Feng Zhang's lab at the Broad Institute published a paper shortly after, in early 2013, demonstrating its successful use in eukaryotic cells (human and mouse).
Since 2012, CRISPR-Cas9 technology has triggered a revolution in the life sciences. It is widely used in basic research to study gene function and create disease models. In medicine, it is being developed for gene therapies to treat genetic disorders like sickle cell anemia and cystic fibrosis, as well as for creating more effective cancer immunotherapies. In agriculture, it is used to develop crops with improved traits like drought resistance and higher nutritional value. Its relative ease of use and affordability have led to its rapid adoption in labs worldwide.