Editing Epigenetics (section)

====Non-homologous end joining can cause some epigenetic marker alterations====
[[Non-homologous end joining]] (NHEJ) repair of a double-strand break can cause a small number of demethylations of pre-existing cytosine DNA methylations downstream of the repaired double-strand break.<ref name=Cuozzo /> Further work by Allen et al.<ref name="pmid28423717">{{cite journal |vauthors=Allen B, Pezone A, Porcellini A, Muller MT, Masternak MM |title=Non-homologous end joining induced alterations in DNA methylation: A source of permanent epigenetic change |journal=Oncotarget |volume=8 |issue=25 |pages=40359–40372 |date=June 2017 |pmid=28423717 |pmc=5522286 |doi=10.18632/oncotarget.16122 |url=}}</ref> showed that NHEJ of a DNA double-strand break in a cell could give rise to some progeny cells having repressed expression of the gene harboring the initial double-strand break and some progeny having high expression of that gene due to epigenetic alterations associated with NHEJ repair. The frequency of epigenetic alterations causing repression of a gene after an NHEJ repair of a DNA double-strand break in that gene may be about 0.9%.<ref name="pmid18704159"/>