In addition to the previously known Cas9 and Cas12 enzymes that target DNA, Zhang and Koonin found a class of enzymes that target RNA.3 They became known as Cas13. Cas13 had the same odd trait as Cas12: when it found its target, it went into a cutting frenzy. The Cas13 not only cut its targeted RNA, it then proceeded to cut up any other nearby RNA.
