Circadian Clock / Circadian rhythm

All mammals have an internal 24-hour timekeeping system called the circadian clock. It helps the body prepare for predictable daily changes in the environment (Henao-Mejia et al. 2012 Nature 482(7384): 179-85). A master clock in the brain's suprachiasmatic nucleus (SCN) coordinates subsidiary clocks in organs such as the liver, fat tissue, muscle, and gut (Tahara et al. 2018 Sci Rep 8: 1395). These clocks are driven by core clock genes: Clock, Bmal1, Period (Per1/2), and Cryptochrome (Cry1/2) (Takahashi 2017 Nat Rev Genet 18: 164-179). Clock genes control the rhythmic activity of 10–50% of all genes in the body, depending on the tissue (Segers & Depoortere 2021 Nat Rev Gastroenterol Hepatol 18: 239-251). The clock governs key body functio…