CRISPR/Cas9 is a powerful tool for gene editing, and it can also be used for genetic screens. However, the single-guide RNA (sgRNA) that targets Cas9 can have off-target effects. Now John Doench, David Root, and colleagues at the Broad Institute of MIT and Harvard used recent sgRNA design rules to generate sgRNA genome-wide libraries with enhanced on-target activity and reduced off-target effects. They also profiled the off-target effects of thousands of sgRNAs to develop a new tool to help scientists predict off-target sites for their sgRNA. Published in Nature Biotechnology.
