Research sheds light on body clock and links to mental health and disease

A large-scale genomic analysis has revealed 327 areas of the body clock genome, suggests that being genetically programmed to rise early may lead to greater wellbeing and a lower risk of schizophrenia and depression.

The study highlights the key role of the retina in the eye in helping the body to keep time, using 450,000 people in the UK Biobank study and 250,000 participants from 23andMe. It was led by the University of Exeter and Harvard Medical School and funded by the Medical Research Council and published in Nature Communications. It also increases the number of areas of the genome known to influence whether someone is an early riser from 24 to 351.

"The discovery of this fundamental body clock mechanism in the brain recently won the Nobel prize for medicine in 2017. However, we still know very little about whether or not your body clock influences your risk of disease."

Lead author Dr Samuel E. Jones, of the University of Exeter Medical School

All participants were asked if they were a “morning person” or an “evening person”, and their genomes were analysed to look at which genes they had in common which may influence their sleep patterns.

The researchers confirmed their results using information from wrist worn activity trackers worn by more than 85,000 individuals In the UK Biobank. This information showed that the genetic variants the researchers identified could shift a person’s natural waking time by up to 25 mins- changing some people’s waking time from 8am to 8.25am, for example. The researchers found that the genetic areas influence sleep timing, but not the quality or duration of sleep.

The genomic regions identified include those central to our body clocks, also referred to as circadian rhythms, as well as genes expressed in the brain and in retinal tissue in the eye. The body clock cycle is slightly longer than the 24 hour daily cycle. The eye tissue connection may help explain how the brain detects light to “reset” the body clock each day and to align with the 24-hour cycle.

Our body clocks are influenced by genes and lifestyle factors including diet, exposure to artificial light and our jobs and activities. Our body clock affects a wide range of molecular processes, including hormone levels and core body temperature, as well as our waking and sleeping patterns.