Bioethics Blogs

CRISPR Gene Editing: Proofreaders and Undo Buttons, but Ever “Safe” Enough?

The 1986 Franklin Spelling Ace, a previous generation of spellcheck. Flickr/Nate Bolt

News about genetic engineering continues to emerge at a dizzying pace. In recent weeks, a handful of reports suggest that the suite of new “gene editing” tools may have so-called “proofreaders” and “undo” protocols that increase technical safety. At the same time, a growing consensus seems to be emerging that looks beyond immediate technical safety to the long-term and social implications of modifying the genes of human embryos for the purpose of “enhanced” reproduction.

Is CRISPR safer?

A November 13 story in The Scientist, headlined Cas9 Proofreads Gene Edits, canvassed two recent research publications (in Nature and Science) co-authored by CRISPR co-discoverer Jennifer Doudna. The take-home message was that the Cas9 protein – the molecule charged with making cuts to DNA in the CRISPR/Cas9 gene editing complex – may have certain built-in mechanisms that work against off-target cuts. The headline’s metaphorical imagination conformed to the headline used by UC Berkeley in its related November 12 press release: CRISPR-Cas9 gene editing: check three times, cut once.

The same day, VICE Motherboard reported on work done by researchers at UMass Medical School (published in Molecular Therapy)that “used a ’non-cutting’ version of the protein Cas9” to research the genetics of muscular dystrophy. In contrasting the UMass team’s research with the typical function of CRISPR/Cas9 complexes, VICE’s Melissa Cronin wrote descriptively,

Usually, CRISPR is a cutting machine, hacking away at pathogenic genes. But sending a weed-whacker into a delicate genome to cut away hundreds of spots is risky, and could result in mistakes.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.