Figure 1 .

Senescence-associated chromatin changes. Globally, heterochromatin (shown in blue) is lost, but there are additional focal gains of heterochromatin [15–17]. In OIS, SAHFs (shown in green) are formed [18]. Canonical histones become less prevalent, whereas increased proportions of histone variants are observed [19–23, 47, 49]. Modifications to histones drive a senescence-associated transcriptional program [24–27, 65]. Acetylation = Ac, Methylation = Me.