Useful, but rare
Six hours of sleep is enough for the owners of a successful mutation
A group of scientists from the United States has identified a mutation that allows people to sleep only 4-6 hours a day and feel well-rested at the same time.
The mutation was found in members of the same family: four men and two women. In all these people, in the ADRB1 gene located in the short arm of the tenth chromosome, one cytosine was replaced by guanine, which caused the replacement of one amino acid in the corresponding protein: valine is present there instead of alanine. This mutation is very rare. As follows from the Exome Aggregation Consortium database, 4 people per 100,000 have it. The protein encoded by the mutation is a receptor for norepinephrine.
The researchers found that the neurons of the brain stem of mice, which have many such receptors in their membrane, are active during wakefulness and calm during the deep sleep phase. Stimulation of these neurons leads to instant awakening even in this phase of sleep. It is assumed that the detected mutation makes such neurons more active, which facilitates the process of awakening and allows people to be content with a shorter sleep duration. The authors of the work created genetically modified mice with a similar mutation and found out that these mice sleep on average an hour less than normal mice.
The mutation of the ADRB1 gene was not the first mutation known to science that reduces the need for sleep. In 2009, a mutation in another gene, DEC2, was described. The mother and daughter who had it could also sleep for only 6 hours, and this was enough for them to have a good rest. The DEC2 gene encodes a protein that helps turn off a number of others, including the gene for the hormone orexin, which keeps the body awake.
The study was published in the journal Neuron (Shi et al., A Rare Mutation of β1-Adrenergic Receptor Affects Sleep/Wake Behaviors).
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