Tick ... tock ... How the biological clock keeps us running

Every morning in millions of bedrooms, humans are caught in between the battle of the clocks, pitting the alarm clock and its shrilling, on one hand, against the invisible body clock that ticks soundlessly, on the other.

At first the body clock seems to hold sway as a sleepy-eyed human taps on the snooze button for just another 10 minutes of sleep, but eventually the alarm clock wins, and the groggy-eyed human shuffles out of bed to face the day.

We may not see it, but we have an internal “clock”, called the circadian rhythm, that helps us anticipate and adapt to the rhythm of the day which in turn pays homage to the rotation of the earth.

Biological clocks are found in nearly every tissue and organ. They are composed of specific molecules (proteins) that interact in cells throughout the body to determine the particular ways that your body behaves in particular times of the day.

The body clock ramps up the engine at the start of a new day, regulating our sleep, wakefulness and eating patterns, blood pressure and the release of hormones, among other body functions, as per a set schedule.

Our moods, hormone levels, body temperature and metabolism rise and fall to the rhythm of the biological clock.

 Scientists have long been fascinated by the circadian rhythm. Among them Jeffrey Hall, Michael Rosbash and Michael Young, American geneticists who were awarded this year’s Nobel Prize in Medicine, for shedding light on the internal biological clock that governs the wake-sleep cycles of most living things; particularly “how plants, animals and humans adapt their biological rhythm in synchrony with the earth’s revolution.”

While studying fruit flies, whose biological clocks use the same principle as those in humans and other organisms, Jeffrey Hall and Michael Rosbash isolated a section of DNA called the period gene.

This gene contains instructions for making a protein called PER, which controls an organism’s daily rhythm.

The levels of PER oscillate over a 24-hour cycle, rising during the night and falling during the day.

As a result, levels of the PER protein oscillate over a 24-hour cycle – rising during the night and falling during the day.

The third awardee, Michael Young, discovered two genes – timeless and doubletime – which affect the stability of PER.

If PER is more stable, the body clock ticks slower and if it is less stable, it ticks faster.

 The stability (or instability) of PER is one reason why some people work best in the mornings, while others are night owls.

While announcing the award, one Nobel Committee member said that the discovery of the molecular clock can raise awareness on the importance of proper sleep hygiene, making certain that people go to sleep at an hour that is suitable.

The committee noted that the laureates’ findings had vast implications for human health and wellbeing.

When there is a mismatch between our internal clock and the external surroundings, it can affect the organism’s wellbeing – for example, people experience jet lag after a trans-Atlantic flight.

Moreover, body clock disruption affects memory formation in the short term, and increases the risk of diseases like type 2 diabetes, cancer and heart disease in the long term.

PREVIOUS WINNERS

2016: Yoshinori Ohsumi for discovering how cells remain healthy by recycling waste (Autophagy).

2015: William C Campbell, Satoshi Ômura and Youyou Tu for anti-parasite drug discoveries.

2014: John O’Keefe, May-Britt Moser and Edvard Moser for discovering the brain’s navigating system.

2013: James Rothman, Randy Schekman, and Thomas Sudhof for their discovery of precisely how cells transport material.

2012: Two pioneers of stem cell research - John Gurdon and Shinya Yamanaka - were awarded the Nobel after changing adult cells into stem cells.

2011: Bruce Beutler, Jules Hoffmann and Ralph Steinman shared the prize after revolutionising the understanding of how the body fights infection.

2010: Robert Edwards for devising the fertility treatment IVF which led to the first “test tube baby” in July 1978.

2009: Elizabeth Blackburn, Carol Greider and Jack Szostak for finding the telomeres at the ends of chromosomes.