Genome editing is one of the forefront topics of science with vast potential uses. One large application is the effects that precise genome editing will have on the field of regenerative medicine. Precise genome editing for therapeutic purposes is difficult to achieve because it requires the pathway of homology directed repair (HDR) to be active rather than non-homologous end joining (NHEJ) which results in deleterious insertions or deletions in the DNA. These pathways are distinct and are regulated by different enzymes. These pathways are both activated as a response to double stranded break in the genome. While NHEJ as a pathway is much more favored as a mechanism for repair we in the Srivastava/Conklin laboratories are much more interested in HDR due to its therapeutic uses. We developed an assay based on droplet digital PCR (ddPCR) to quantify HDR and NHEJ at the same time. This powerful technique allows us to use a variety of different nucleases and nickases and test each of their abilities to induce HDR while at the same time measuring the activity of NHEJ. We attempt to find the best cutting tool that will allow us to maximize the amount of HDR while at the same time minimizing the activity of NHEJ.