Night Owl or Morning Person: The Genetics

You may be the type of person that gets up at the crack of dawn full of energy, while your spouse seems to get motivated as soon as the sun goes down. Some people attribute this to some sort of disorder or poorly regulated schedule. While there are some disorders that interrupt proper sleep habits, scientists have found some genetic links to differences in waking and sleeping times.

Body Clocks

Most animals and humans are set to a certain body clock. These are called circadian rhythms. Genetics in animals have been found to possibly play a part in their sleep and waking cycles. This is not hard to believe, as there are many nocturnal animals. New studies have brought humans into the picture to find out if our genetics are causing some of the variations in our species, as well.

The Study 

Almost 90,000 people were given questionnaires on their sleeping and waking habits. All of the participants also submitted a DNA sample. Researchers call this type of study a genome-wide association study (GWAS). A percentage of the subjects were tossed out of the study, as they stated they had no preference of day or night rising. A little over 75 percent remained, however, and had a specific preference.


There ended up being a few genetic variants that played a part in the preference towards morning. Of the 15 variations, seven were close to genes that played a part in circadian rhythms. Others were located near light sensing genes. It seems these genes play a part in telling the body when to wake up.

Some other observations include differences between women and men. A larger percentage of women identified as morning people than men. Older individuals also seemed to prefer mornings. Night owls were also more likely to have clinical sleep disorders, such as insomnia and sleep apnea. They were also more likely to have issues with depression.

Many people identify as a night owl or morning person. Most of us know someone who is one or the other. We may even have our own preference. Some people can drink coffee all morning and barely get moving. Others hop out of bed ready to face the day with no caffeine necessary. It is interesting to think about the genetics of animals that roam around at night with a varying circadian rhythm. Now we know that humans may have some genetic differences, as well.

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