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. Author manuscript; available in PMC: 2017 Jan 1.
Published in final edited form as: J Cell Physiol. 2016 Jan;231(1):15–24. doi: 10.1002/jcp.25053

Figure 3. Opportunities for mutagenesis during homologous recombination repair of a DNA double-strand break.

Figure 3

A. Creation of a DNA double-strand break. B. Resection of broken ends creates 3’ single-stranded DNA that can be easily damaged. C. One-ended strand invasion into a homologous template creates a displacement (D)-loop. Synthesis during D-loop extension is potentially mutagenic. Initial strand invasion can also occur at homeologous or microhomologous sequences, resulting in insertion/deletion repair products. D. During synthesis-dependent strand annealing (SDSA), D-loop dissociation and annealing of the nascent strand with single-stranded DNA from the broken chromosome is followed by potentially mutagenic single-stranded gap filling and ligation. E. Alternatively, two-ended invasion and synthesis leads to double Holliday junction (dHJ) formation. Resolution of the dJHs can create crossover (shown) or non-crossover (not shown) products. Asterisks indicate new potential sites of mutagenesis at each step.