In order to assess whether MEP strains could be useful for analyzing LOH rates in aging yeast cells, we first examined whether old mother cells produced daughters that retained respiration competence. Specifically, we examined the inheritance of respiration competence in daughter cells of a MEP strain (UCC5185) using pedigree analysis. We found that ∼65% of the mother cells produced daughters with respiration competence through their entire RLS (Median of 36 generations, Figure S1A). This is in striking contrast to the strain we originally examined for age-associated LOH (UCC809), where only ∼5% of the mother cells produced respiration-competent daughters throughout their life span (Figure S1A and [11]–[12]). Furthermore, for those UCC5185 mother cells that did produce respiration-incompetent daughters, the median age at which this occurred was significantly later in the mother's life span (23 generations versus 10 generations in UCC809) (Figure S1B). Together, these results demonstrate that the majority of UCC5185 cells are capable of producing respiration-competent daughters throughout their life span, thus providing the basis for our analysis of LOH in such a population.
