Incisions for excision

Excison implies two incisions. Plumbers and surgeons know this principle, and long ago it was put into practice by the evolutionarily ancient DNA-repair machinery. Dissection of the first incision made by the eukaryotic nucleotide-excision repair pathway has now been described by O'Donovan et al., and dissection of the second by Bardwell et al. When put together the two processes enable the replacement of a damaged piece of DNA by a new one. [...]
One might predict that a category of patients will be found that are deficient in nucleotide-excision repair and also have symptoms of a recombination defect. If these striking multiple engagements reflect a general evolutionary strategy of function sharing, then intimate connections between nucleotide-excision repair and cell-cycle control or chromatin dynamics are bound to show up as well.