The protein deacetylase Sir2 has been implicated in the yeast aging process and life span determination [32]. Furthermore, loss of Sir2 function leads to high rates of USCE in haploid cells, resulting in dramatic copy-number instability within the rDNA array [33]–[35], and increased rates of homologous recombination between rDNA arrays in diploid cells [11]. Therefore, we examined the potential role of Sir2 in age-associated LOH in detail.
