A method of site-specific modification of an endogenous target DNA of a eukaryotic cell is provided. The method includes contacting the endogenous target DNA having an intended modification site with (i) a gene editing system configured to introduce a double strand break in the endogenous target DNA at or near the intended modification site, and (ii) a donor DNA repair template comprising a plurality of tandem repeat sequences. In the method, each of the plurality of tandem repeat sequences comprises an exogenous donor DNA sequence flanked by a donor 5′ flanking sequence and a donor 3′ flanking sequence. The donor 5′ flanking sequence and the donor 3′ flanking sequence are homologous to a continuous DNA sequence on either side of the intended modification site in the endogenous target DNA.