[extropy-chat] sleep mutation

[Damien Broderick]

The Times:

A GENE that could explain why some people can get by on just a few hours' 
sleep each night has been discovered by US researchers.

A small mutation in a gene known as the Shaker - also nicknamed the 
"Thatcher gene" after the former British prime minister who famously needed 
little sleep - allows fruitflies to thrive on a fraction of the sleep they 
usually require, according to researchers at the University of Wisconsin 
Medical School.

The Shaker gene controls the flow of potassium into cells, which affects 
their electrical activity. Several other studies have shown that a similar 
process affects human sleep: in mammals, potassium channels in nerve cells 
are important to the generation of "slow waves" that occur in the brain 
during deep sleep.

"Humans have the same kind of genes and potassium channels and we know that 
slow waves must be generated by changes in the excitability of neuron cell 
membranes," said Chiara Cirelli, who led the research.

Naomi Rogers, a sleep expert and senior research fellow at the Woolcock 
Institute of Medical Research in Sydney said researchers had suspected for 
some time that individual genes might determine how much sleep people need.

"Often it's been in families that you see these sort of traits where people 
need little sleep, so it's not surprising that there's a gene or a group of 
genes that is responsible for this," she said.

The study found that a particular mutation in the Shaker gene led 
Drosophila fruitflies to sleep for a third as long as usual, without 
impairing performance. Dr Rogers said less than 10 per cent of the 
population were "short-sleepers" - people who could exist on three or four 
hours of sleep a night.

"People are working longer hours or shift work, they have family 
commitments, a lot of businesses are global 24 hours a day, seven days a 
week, so we're getting less sleep," she said.

"The military, for example, is quite interested in looking at this."