The first patient edited “in vivo” last week is a breaking news story, and zinc finger nuclease ZFN must be credited for the accomplishment. A putatively outdated system stealing the scene from the most celebrated technique for gene editing is a bit like Carl Lewis beating Usain Bolt at the Rio Olympics. Any wonder that tweets by some biotech-enthusiasts had something of a derby atmosphere, while many inattentive readers thought it was CRISPR stuff, as lay people never heard of ZFN before.
Genome editing did not happen out of the blue when CRISPR was born in 2012, but it’s CRISPR that made it so popular in labs and the media worldwide. Mario Capecchi came first with “gene targeting” in the late 1980s, then ZFN debuted in the 90s, joined by TALEN in the following decade. Every editing technique has its pros and cons, regarding efficiency, precision, delivery, etc. CRISPR, however, is deemed revolutionary because it’s so cheap, easily programmable, fast-evolving and even multiplexable. Not to mention that academic and non-profit researchers are freely using CRISPR, while ZFN was virtually monopolized by the company Sangamo.
It remains to be understood if ZFN has evolved into something new, while we were busy following CRISPR’s advancements (from high-fidelity variants to base editors). Perhaps it’s a tale of Carl Lewis’s son eclipsing Bolt last week. Let’s wait for the scientific papers after the press-releases. Meanwhile, I temporarily declare myself ZNF-passionate besides being crazy for CRISPR. A question for sports fans in the end: who will be the next Bolt anyway?
P.S. This is the first “in vivo” treatment involving gene editing, meaning that it was performed directly into the body. Both ZFN and CRISPR have already been employed in cells taken from patients, manipulated “ex vivo” and finally reintroduced.