The CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a genome-editing tool. Cas9 is an enzyme that is produced by the system. When the target DNA is detected, the CRISPR system uses Cas9 and “binds to the DNA and cuts it, shutting the targeted gene off.” (Broad Institute- broadinstitute.org) This allows researchers to look at a gene and study its specific function. Using Cas9, researchers are able to activate specific gene expressions instead of cutting the DNA. Compared to other systems, the CRISPR-Cas9 can cut DNA strands itself. This is beneficial, as the system doesn’t need to be paired with separate cleaving enzymes. This system is valuable to scientists as it allows them to create cell and animal models quickly. Researchers then use these models to study diseases such as cancer and mental illnesses. The improvement of these systems, allowing for faster research, is important especially as the population continues to increase.