Correction to: Nature Protocols 12, 828–863 (2017) https://doi.org/10.1038/nprot.2017.016, published online 23 March 2017

In the published version of this paper, Step 64 of the Procedure reads, “Refer to Steps 37–39 for NGS analysis of the sgRNA distribution.” This step should refer the reader to Steps 35–39. This text has not been corrected in the original paper.