Why we need DAR
When a lesion
occurs in the transcribed strand (TS) TCR removes it together with ~30
nucleotides then fills the gap using the non-transcribed strand (NTS)
as a template.
If lesions were
allowed to accumulate in the NTS over a lifetime, it is likely that
there could be one within the gap created by TCR. This may lead to the
introduction of a mutation when filling the gap.
this by maintaining the NTS free of lesions in spite of the lack in
global genome repair.