Proc Natl Acad Sci U S A. 2018 Apr 3;115(14):3669-3673 doi:10.1073/pnas.1718148115

Alejandro Chavez, Benjamin W. Pruitt, Marcelle Tuttle, Rebecca S. Shapiro, Ryan J. Cecchi, Jordan Winston, Brian M. Turczyk, Michael Tung, James J. Collins and George M. Church.

Precise Cas9 targeting enables genomic mutation prevention.

Destabilising mutations in the guide RNA allow for discrimination of SNPs. The targetted SNP is not in the host genome at the moment that the prevention system is inserted.