Until recently, the connection between aging and DNA repair has rested on two classes of observation.
First, DNA damage and unrepaired double-strand breaks (DSBs) accumulate with age.
Second, several defects in DNA repair genes are associated with early onset of age-related diseases and other signs of premature aging.
Now, a third link has emerged.
The mechanisms by which cells repair DSB damage can change dramatically with age, shifting from simpler end-joining processes in younger organisms to homologous mechanisms in which missing genetic information is restored through use of a template.
So far this third link between aging and DNA repair has only been observed in a small number of experimental systems, and cannot yet claim the generality of the other two.
Experimental study on this third link could be found in the source article.