Deep sleep, evening owls and genes

Researchers in two studies say they’ve discovered a “sleep gene” and a “night owl variant” that may help explain different sleep patterns.

Do you toss and turn in bed and wake up every few hours while your partner sleeps soundly and peacefully?

Do you find it impossible to get to sleep before midnight while others you know stumble into bed and fall deep into dreamland at 10pm?

All of this can have a biological reason.

In two studies published this week, researchers say they have discovered variations in genes that could explain why some people have trouble sleeping and other people are so-called “night owls.”

Still, the researchers say, many questions remain unanswered.

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The first study was published in the journal Science Advances on Wednesday.

In it, the researchers focused on genes that change expression in the sleep-wake cycle.

The researchers studied mice and discovered the daytime altered expression of the gene FABP7 in the brains of small rodents.

They noticed that mice with a “knocked out” FABP7 gene slept more restlessly. The researchers concluded that a specific gene is necessary for normal sleep in mammals.

The researchers also checked the FABP7 gene in humans.

They combed through data on nearly 300 Japanese men who took part in a sleep study that included DNA analysis.

In 29 of the men, the FABP7 gene appeared to be malfunctioning and these men slept restlessly. The researchers said the men got as much sleep as other participants, but they experienced more waking moments and didn’t sleep as soundly.

Finally, the researchers created transgenic fruit flies by inserting mutated and normal human FABP7 genes into the insects.

The researchers said they noticed restless sleep in the flies that had the mutated gene.

“Sleep has an important function to perform,” said Jason Gerstner, PhD, an assistant research professor at Washington State College of Medicine and the paper’s lead author, in a press release. “But as scientists, we still don’t understand what that is. One way to get closer to that is to understand how it is regulated or what processes exist that are shared by all species.”

Gerstner said other genes are almost certainly involved in the sleep process. He and his team hope to find these biological compounds as well.

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The second study was published today in the journal Cell.

In it, researchers say they have discovered a variant in the CRY1 gene that slows down a person’s biological clock.

This so-called “circadian clock” determines when a person feels sleepy each night and when it’s time to wake up.

People with the “night owl variant” have a longer circadian cycle, which causes them to stay awake later, the researchers said.

For their study, Michael W. Young, PhD, head of the Rockefeller Genetics Laboratory, and research associate Alina Patke collaborated with sleep researchers at Weill Cornell Medical College.

They observed volunteer participants for two weeks in a lab apartment isolated from any cues as to the time of day. Participants were allowed to eat and sleep whenever they wanted.

According to Young, most people follow a typical 24-hour sleep-wake cycle. However, a person with delayed sleep phase disorder (DSPD) did not follow this pattern.

Among other things, the researchers found that the release of melatonin was delayed in this individual. This chemical helps you fall asleep.

“Melatonin levels start to rise around 9 or 10 a.m. for most people,” Young said in a press release. “With this DSPD , that doesn’t happen until 2 or 3 a.m..”

When researchers checked the DNA of the DSPD participant, they said the mutation in the CRY1 gene stood out.

They said this gene mutation made the CRY1 protein more active and kept other clock genes turned off for a longer period of time.

“This is a pretty powerful genetic change,” Young said.

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The researchers said that sleep abnormalities are not something to dismiss.

Someone with a “Night Owl” variant can go to bed later, but must get up before their body is ready to return to the waking state.

The Centers for Disease Control and Prevention (CDC) estimate that at least 50 million Americans suffer from a sleep disorder.

They refer to insufficient sleep as a public health problem.

Young and his team plan further research. Part of that effort will be finding solutions.

“Just finding the cause doesn’t immediately fix the problem,” Patke said in a press release. “But it is not unthinkable that drugs based on this mechanism could be developed in the future.”

Right now, people with insomnia can help alleviate the problem by sticking to strict schedules.

Young added that they can also be exposed to strong light during the day.

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