In the 1980s, scientists discovered that bacterial genomes held arrays of repeating DNA sequences with unique intermittent strings of viral DNA. They named this configuration Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and later found to it to work in combination with CRISPR-associated (Cas) enzymes to edit viral genetic information.
Since then, scientists have adapted Cas9 enzymes from bacteria to cut and edit the genome of virtually any organism. What makes the CRISPR-Cas9 pair unique is its unrivaled precision, efficiency, and flexibility. Researchers now have an extremely accurate means of targeting and studying particular DNA sequences in vast genomes. Experiments using genetically-engineered organisms that traditionally take a year or more to complete can now be accomplished in just a few months with CRISPR. Furthermore, modifications to CRISPR, such as the disruption of Cas9 enzymes, have opened up expansive paths of study in various subfields such as epigenetics.
CRISPR has already been proven to prevent HIV infection in human cells. Now it is entering clinical trials as a form of immunotherapy for cancer patients. Although CRISPR is currently a mere first generation tool, it will undoubtedly continue to transform the fields of biology and medicine.
By Jim Xie
References may be found in the journal.