Are you an early bird or a night owl? It’s in your DNA

Are you a morning person, or a night owl?

Being more suited to rising early and going to bed early, or preferring to burn the midnight oil, is at least partly down to our DNA, according to new research published in the journal Nature Communications.

While previous studies indicate BMI, alcohol consumption, light exposure and depression, among other things, can affect circadian rhythm (sleep-waking cycles), a new paper which analysed the genetic make-up of nearly 90,000 people shows genes have a part to play.

Researchers analysed thousands of saliva samples given to the company 23andMe, which performs DNA testing. After registering with 23andMe, customers send in samples to be analysed for ancestry, disease profiles and other genetic information.

Results given to the company’s users include their Neanderthal ancestry percentage and information about hereditary diseases they may be carriers for. Customers can also consent to have their data used for larger studies.

Researchers surveyed people already profiled on 23andMe to establish whether they were a “night person” or a “morning person”.

Those who were considered to be neutral were disregarded. Only participants of European descent to standardise the sample, and related individuals were also removed; this left 89,283 people.

In those who identified as “morning people”, researchers found 15 common single nucleotide polymorphisms (SNPs) - a type of variation in a DNA sequence used in genetic analysis. This evidence suggests that apart from other factors, being chirpy in the morning time is at least somewhat hardwired.

The study also found that “morningness” is more prevalent in women, with 48.4 per cent reporting being morning people, compared to 39.7 per cent of men.

Morningness also increases with age: only 24.2 percent of under-30s report being morning people, while the over-60s surveyed had 63.1 per cent early birds.

The full research paper is open-access and can be found here.