A Natural Polymorphism in rDNA Replication Origins Links Origin Activation with Calorie Restriction and Lifespan
(A and D) Mean RLS distribution of 28 segregants with SIR2 deleted (A) or 9 segregants overexpressing SIR2 (D). Segregants with the RM rDNA locus were longer-lived than those inheriting the BY rDNA locus even in the absence of SIR2 (17.0±2.1 vs. 10.8±1.7, P = 6.1×10−9, ν = 2) or with SIR2 overexpression (35.4±3.4 vs. 28.1±3.0, P = 2.0×10−2, ν = 2). (B, C, E and F) Lifespan measurements (n = 40 cells) for the backcrossed BY and RM strains containing BY or RM rDNA and sir2Δ or fob1Δ. Mean lifespans for each strain are given in parentheses.