Great line in a Gizmodo story (worth reading: right here) about a variant of the CRISPR technique being eyed for killing “superbug” bacteria that are resistant to antibiotics:
If CRISPR-Cas9 is a genetic scalpel, CRISPR-Cas3 is a chainsaw.
As the story explains, Cas3 is a different enzyme than Cas9 so it acts differently when used with the CRISPR process. “Like Cas9, the Cas3 enzyme can be programmed to target specific DNA, meaning scientists could train it on an unwanted invader. But Cas9 precisely cuts DNA, leaving a double-stranded break that allows the cell to repair itself once the desired edits have been made. Cas3 is like Pac-Man, chewing up the cell in such a way that leaves it no hope of repair.”
Science Cafe New Hampshire discussed CRISPR in Nashua a year ago. Hope you were there.