(c) Relative acetylation (normalized to wild-type controls at each day) of indicated histone H3 Lys residues of Δspe1 cells (open bars), compared with wild-type cells (closed bars) during chronological ageing. Data represent means ± s.e.m. (n = 3). P values indicate the result of a two-factor ANOVA corrected by Bonferroni post hoc test. 