Compositions and methods concern the sequence modification of an endogenous genomic DNA region. Certain aspects relate to a method for site-specific sequence modification of a target genomic DNA region in cells comprising: transfecting the cells by electroporation with a composition comprising (a) a DNA oligo； (b) a DNA digesting agent； and (c) a targeting RNA, wherein the targeting RNA is capped and/or polyadenylated； wherein the donor DNA comprises: (i) a homologous region comprising nucleic acid sequence homologous to the target genomic DNA region and (ii) a sequence modification region； and wherein the genomic DNA sequence is modified specifically at the target genomic DNA region.
