Hatada, S. et al. Stem Cells Transl. Med. 4, 1–13 (2015).

Efficient genome-editing tools are needed to correct patient-derived stem cells or model human disease. To engineer targeted changes, scientists have to use editing methods that rely on the generation of double-stranded DNA breaks and their subsequent repair by homologous recombination, which can replace cut DNA with a donor vector sequence but is inefficient. Hatada et al. report that low (0.4 Gy) doses of g-ray or X-ray radiation can increase recombination efficiency in cells by more than 30-fold when used in combination with zinc finger nucleases, transcription activator–like effector nucleases or CRISPR nucleases. The limited exposure to low radiation is safe at the karyotypic and functional levels and may work by 'priming' the repair apparatus of the cell. The authors edited three genomic loci and suggest the potential for high-throughput genome editing.