Figure 1. Repair of DSBs.

With the creation of each DSB, two DNA repair processes proceed in concert. HDR results in high-fidelity repair using a template strand. If desired, an exogenous oligonucleotide sequence can be introduced to achieve site-specific mutagenesis. NHEJ yields WT clones as well as clones with frameshift/indel mutations through its inherently more error-prone mechanism of repair.