Lethargic lab mice and the science of slumber

A team led by a researcher from the University of Tsukuba have identified two mouse genes that may have a role in regulating sleep. Most people spend a third of their life asleep and yet we remain in the dark about the genetics behind our nocturnal needs.

In order to shed light on this fundamental question, the researchers observed the sleeping habits of 8,000 mice that carried a range of random genetic mutations hoping to spot unusual slumbering behaviour that could be linked to individual genes.

One group, nicknamed Sleepy, went into deep sleep for almost a third longer than average mice and were more sensitive to sleep deprivation. A second, dubbed Dreamless, spent 44 per cent less time in the lighter rapid-eye-movement (REM) sleeping state which is associated with dreaming in humans. These effects were linked to mutations in the multifunctional Sik3 gene, and Nalcn, a gene that may control neuron excitability, respectively.