23andMe: Being a 'Morning Person' has a Genetic Basis

That morning person you know at work who starts off the day alert, chipper and productive may just simply be wired that way in their DNA, according to a new study by the genetics company 23andMe.

Those same morning people are also generally older and female, and less likely to be obese and suffer from depression, according to the company’s new study, in the journal Nature Communications.

“Morningness is associated with insomnia and other sleep phenotypes, and is associated with body mass index and depression but we did not find evidence for causal relationship,” write the authors. “Our findings reinforce current understanding of circadian biology and will guide future studies.”

The 15 genetic variants were connected to circadian rhythms and self-reported “morningness,” according to the study, which involved 89,283 people. Four of the variants had never previously been connected to sleep cycles.

Some eight million variants overall were analyzed in the genomes of the subjects, all of whom had 97 percent or more European heritage. They adjusted for alcohol and nicotine abuse, and caffeine use.

The targeted part of the DNA concerned the suprachiasmatic nucleus (SCN) in the hypothalamus.

The morning people found in the study were also less likely to have insomnia, and less likely to require eight hours of sleep.

“Morning persons are significantly less likely to have insomnia. They are also less likely to require (8 hours or more) of sleep per day, to sleep soundly, to sweat while sleeping, and to sleepwalk,” the authors find. “Morning is also associated with lower prevalence of depression.”

The 23andMe scientists also plotted the customers whose “morningness” and “night owl” status was analyzed – and came up with a map showing that morning people were spread out among a far geographic distribution in the United States. The Western states and New England appeared to have the most morning people, but there were parts of the South that also had high percentages of the early risers. Some of the states with the highest proportion of morning people tended to have older populations, they add.

“Some circadian rhythm genes we identified have been studied in model organisms, but much less so in humans,” said David Hinds, principal scientist at 23andMe. “We also identified new genes that have not previously been associated with sleep behavior.”

Circadian rhythm has become a major focus for brain researchers. Earlier this month a University of Pittsburgh team of psychiatrists talked with Laboratory Equipment [1] about their latest study about how the natural rhythms of the body could be the next major treatment target for mental illness and psychiatric disorders, and even addiction.