CRISPR, for those of you who do not know, is an anti-viral immune system found in archaea and bacteria, that until a few years ago, was all but unknown outside the small group of scientists have been studying it since its discovery a quarter century ago. This all changed in 2012, when a paper from colleagues of mine at Berkeley and their collaborators in Europe described a simple way to repurpose components of the CRISPR system of the bacterium Streptococcus pyogenes to cut DNA in a easily programmable manner.