Tick, Tock! The Molecular Basis of Biological Clocks

A long time ago, before the rise of humans, before the first single celled organisms, before the planet even accumulated atmospheric oxygen, Earth was already turning, creating a 24-hour day-night cycle. It’s no surprise, then, that most living things reflect this cycle in their behavior. Certain plants close their leaves at night, others bloom exclusively at certain times of day. Roosters cock-a-doodle-doo every morning, and I’m drowsy by 9:00 pm every night. These behaviors roughly align with the daylight cycles, but internally they are governed by a set of highly conserved molecular circadian rhythms.

Jeffrey Hall, Michael Rosbash and Michael Young were awarded the 2017 Nobel Prize in Physiology/Medicine for their discoveries relating to molecular circadian rhythms. The official statement from the Nobel Committee reads, “…this year’s Nobel laureates isolated a gene that controls the normal daily biological rhythm. They showed that this gene encodes a protein that accumulates in the cell during the night, and is then degraded during the day. [They exposed] the mechanism governing the self-sustaining clockwork inside the cell.” What, then, does this self-sustaining clockwork look like? And how does it affect our daily lives (1)?

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