Fig. 8.

Mechanisms of DNA repair outcomes of genome editing. Typically, DNA double-strand (ds) breaks caused by CRISPR/Cas9 are repaired via either homology-directed repair (HDR) or non-homologous end joining (NHEJ), depending on the circumstances. Exogenous ‘repair templates’ can be introduced into the genome by HDR, whereas NHEJ creates random insertions and deletions (indels) that can disrupt coding areas or catalyse genome rearrangements. The preference for HDR or NHEJ after DNA damage can be increased by small compounds that interfere with each system and so bias the cell toward one or the other after DNA damage