Comment on

• High-frequency off-target mutagenesis induced by CRISPR-Cas nucleases in human cells.

  Fu Y, Foden JA, Khayter C, Maeder ML, Reyon D, Joung JK, Sander JD. Fu Y, et al. Nat Biotechnol. 2013 Sep;31(9):822-6. doi: 10.1038/nbt.2623. Epub 2013 Jun 23. Nat Biotechnol. 2013. PMID: 23792628 Free PMC article.
• DNA targeting specificity of RNA-guided Cas9 nucleases.

  Hsu PD, Scott DA, Weinstein JA, Ran FA, Konermann S, Agarwala V, Li Y, Fine EJ, Wu X, Shalem O, Cradick TJ, Marraffini LA, Bao G, Zhang F. Hsu PD, et al. Nat Biotechnol. 2013 Sep;31(9):827-32. doi: 10.1038/nbt.2647. Epub 2013 Jul 21. Nat Biotechnol. 2013. PMID: 23873081 Free PMC article.
• CAS9 transcriptional activators for target specificity screening and paired nickases for cooperative genome engineering.

  Mali P, Aach J, Stranges PB, Esvelt KM, Moosburner M, Kosuri S, Yang L, Church GM. Mali P, et al. Nat Biotechnol. 2013 Sep;31(9):833-8. doi: 10.1038/nbt.2675. Epub 2013 Aug 1. Nat Biotechnol. 2013. PMID: 23907171 Free PMC article.
• High-throughput profiling of off-target DNA cleavage reveals RNA-programmed Cas9 nuclease specificity.

  Pattanayak V, Lin S, Guilinger JP, Ma E, Doudna JA, Liu DR. Pattanayak V, et al. Nat Biotechnol. 2013 Sep;31(9):839-43. doi: 10.1038/nbt.2673. Epub 2013 Aug 11. Nat Biotechnol. 2013. PMID: 23934178 Free PMC article.