Other beneficial effects of CLOCK, such as the promotion of cellular circadian clock homeostasis and chondrogenesis (Supplementary information, Fig. S2b, d), may also contribute to its therapeutic effect on age-related articular degeneration.4,10 Taken together, our findings provide new insights that link the circadian clock and epigenetic regulation with aging and emphasize the CLOCK–heterochromatin axis as a novel potential target for the future treatment of aging-associated degenerative disorders. Here, CLOCK is linked to age.