I was in the lab with a lab member of mine, Martin Jinek, who was the person who was doing work on a protein called Cas9, part of the CRISPR system.  We call it CRISPR-Cas9.  And we were trying to figure out how it worked.  It was pretty clearly an RNA-guided enzyme that could find and cut DNA.  And the question was: ”How does it do that? Does it do that, and if it does, how does it work?”

He was doing experiments to answer that question.  And he eventually figured out that this system could be programmed, literally, with different segments of RNA that have the same sequence of chemical letters that match those letters in DNA.  That’s what allows it to be programmed to find and cut DNA at a particular place in a cell.

And this student of mine, whose name is Prashant Bhat, reminded me of a day when he came into the lab to do his experiments. He saw me and Martin Jinek leaning over a light box in our lab — which was a way of visualizing the data from one of Martin’s experiments — in which we were just looking at each other and high-fiving, and we were just so excited.  And why?  It was because that was the first experiment where Martin had showed how the system could be programmed, and also how we could simplify it compared to what nature had done.