Scientists discover a rare sleep gene in a family that needs less than six hours a night each
- Some people may be able to need less than six-and-a-half-hours of sleep to feel well rested
- Researchers have linked it to a mutation in the ADRB1 gene, which increases the activity of the brain cells which promote wakefulness
- In mice who were gene-edited to have the same mutation, they slept an average of 55 minutes less than is normal
Those who claim, like former Prime Minister Margaret Thatcher famously did, to need less than five hours of sleep are met with disbelief by the rest of us.
But short-sleepers really do exist, and a new study now suggests they have a gene which wakes them up.
While most people need around eight hours of sleep a night, feeling foggy and confused if they don’t get it, ‘natural short sleepers’ can feel well-rested after just six hours.
It is impossible to know if Thatcher was a genetically short-sleeper or just forced herself to stay up.
But researchers from the University of California, San Francisco have discovered more than 50 families who require less than six-and-a-half-hours of sleep to get by.
Taking one of these families, they have isolated the genetic mutation which they believe is responsible.
A new study from the University of California, San Francisco has found that some people have a gene that requires them only needing six-and-half hours of sleep to feel well rested (file image)
The culprit is likely to be a gene called ADRB1, which increases the activity of the brain cells which promotes wakefulness, potentially allowing them to stay awake longer.
In the short-sleeping family, all those who needed little sleep shared the genetic mutation, while their longer-sleeping relatives did not have it.
Furthermore, when scientists tweaked the same gene in mice, they slept for 55 minutes less than regular mice.
‘It’s remarkable that we know so little about sleep, given that the average person spends a third of their lives doing it,’ said co-senior author Dr Louis Ptáček, a professor in the department of neurology at the University of California, San Francisco.
‘This research is an exciting new frontier that allows us to dissect the complexity of circuits in the brain and the different types of neurons that contribute to sleep and wakefulness.’
Experts know a great deal about the genetic of circadian rhythms, our natural body clocks, so that predispose some people as early birds and others as night owls.
But less was known about the genes that regulate how much sleep people need until the first family of short-sleepers was discovered a decade ago.
The fact that blood relatives all shared the same tendency to sleep for less than six-and-a-half hours suggested they had a gene in common.
Then more families came forward, with the short-sleeping going back two or three generations, and researchers began sequencing the genes of one of these families.
The results, published in the journal Neuron, show that the ADRB1 gene was different in the family members who reported functioning normally on just six hours of sleep.
The very rare genetic abnormality controls activity in the dorsal pons, a part of the brain linked to sleep.
When the researchers used gene-editing to create mice with the same mutation, they slept an average of 55 minutes less than is normal.
The discovery of a gene important for keeping people awake could lead to new drugs which help people to sleep, but more research is needed to find other genetic causes for short-sleeping.
For future research, the team plans on looking on how the ADRB1 protein functions in other parts of the brain.
‘Sleep is complicated,’ said Dr Ptáček. ‘We don’t think there’s one gene or one region of the brain that’s telling our bodies to sleep or wake. This is only one of many parts.’
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