This kind of negative feedback system is similar to how a thermostat controls the temperature of a room. If the temperature drops below the set point, the thermostat turns on the heater. When the room gets too toasty, the thermostat turns off the furnace. Here, negative feedback – a build up of heat – works to control the heater and maintain a constant temperature.

Now imagine having to repeat this process over and over each day with nearly exact timing. Biological clocks use negative feedback from clock proteins like period to turn themselves on and off again each 24 hours. Additional studies in the Young lab identified other key genes – dubbed Timeless and Double-Time – that fit into this puzzle by controlling how PER travels around the cell to turn itself off each day.

Fitting the cogs together into molecular clocks

Work over the last two decades has rounded out a much deeper understanding of circadian rhythms to show how most organisms have clocks based on feedback loops similar to Drosophila. Rosbash’s lab identified part of the PER protein known as the PAS domains that we now find in many clock proteins from fungi and plants to humans. PAS domains help clock proteins like PER pair up with their partners to control the negative feedback loop.

By comparing differences in the structures of PER PAS domains of Drosophila and mice, scientists are now beginning to learn how the protein “cogs” of the molecular clock fit together to tell time. Understanding circadian rhythms at atomic resolution like this allows us to explain how newly identified mutations in PER lead to changes in clock timing and open the door to therapeutics that could harness the power of circadian rhythms to improve human health.

Living with your clock and its natural rhythms

We now have a much greater appreciation for the central role that circadian rhythms play in coordinating our lives with Earth’s day, controlling everything from your metabolism to the timing of sleep. Young’s lab recently identified a prevalent mutation in a human clock gene, cryptochrome 1, that lengthens the cellular clock and makes it difficult to get to bed before midnight. This inherited “night owl” gene is estimated to be pretty common, found in nearly 1 out of 75 of us.

Understanding the powerful regulation of biology by circadian rhythms is beginning to lead to far-reaching changes in policy. For example, rather than arbitrarily force our sleep schedules into routines that require early morning wake times, some researchers are showing that adjusting our schedules to fit our natural rhythms may pay off at work and school. This is particularly true for adolescents, who have a natural “night owl” tendancydelaying school start times by even just one hour can significantly improve academic performance.

The ConversationThe science is now far enough along in our understanding of circadian clocks that researchers are working to optimize work and sleep schedules with our biology in mind. And all these policy innovations are built on the foundation of the Nobel-winning research with those tiny fruit flies.

This article was originally published on The Conversation. Read the original article.