The genome-editing tool CRISPR-Cas9 is revolutionizing the field of medicine. The technology, which took off in popularity among researchers about five years ago, can precisely edit DNA. The system includes two components: a DNA-cutting enzyme, called Cas9, and a piece of RNA, called guide RNA. A bit of guide RNA targets a specific chunk of DNA, directing Cas9 exactly where in the genome to snip. But slicing and dicing DNA isn’t without risks. Some researchers have been wary from the get-go, perhaps rightly so as details emerge about CRISPR’s sometimes-troubling safety record.
The pro-CRISPR camp scored a win in March, when Nature Methods retracted a 2017 paper that had stirred controversy. The researchers originally said their CRISPR-edited mice had large numbers of so-called off-target mutations that resulted from Cas9 cutting at places other than the intended location. But the journal pulled the study because the authors couldn’t show if the ...
