CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. They belong to a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea. These sequences are derived from DNA fragments of bacteriophages that had previously infected the prokaryote. They form the basis for the CRISPR-Cas9 genome editing technology. CRISPR/Cas9 edits genes by precisely cutting DNA and then letting natural DNA repair processes to take over. The system consists of two parts: the Cas9 enzyme and a guide RNA. The technique makes it simple to precisely change a piece of DNA in one or a few cells in living things, including us.