Genome Engineering

A method of altering target DNA in a cell expressing a Cas 9 enzyme that forms a co-localization complex with a guide RNA complementary to the target DNA and that cleaves the target DNA in a site specific manner comprising

• (a) introducing into the cell a first foreign nucleic acid encoding a donor nucleic acid sequence,
• introducing into the cell from media surrounding the cell the guide RNA complementary to the target DNA and which guides the Cas 9 enzyme to the target DNA, wherein the RNA and the enzyme are members of a co-localization complex for the target DNA,
• wherein the donor nucleic acid sequence is expressed,
• wherein the guide RNA and the Cas 9 enzyme co-localize to the target DNA, the Cas 9 enzyme cleaves the target DNA and the donor nucleic acid is inserted into the target DNA to produce altered DNA in the cell.