By now, you’ve no doubt heard of CRISPR, the latest gene-editing tool sweeping research labs across the globe. It was first discovered in certain strains of bacteria, who use it as an important weapon against dangerous viruses. In bacteria, CRISPR identifies a virus that poses a threat, records the virus’ genetic data and imprints it onto RNA molecules. An immune enzyme called Cas9 grabs one of the RNA molecules and goes exploring. When Cas9 encounters a virus that matches the data on the RNA molecule, it latches on and slices the virus in half to prevent it from replicating and posing any threat.

(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Tina Leaman)