A gene has been linked to quality of sleep.
Researchers have found the FABP7 gene can influence whether sleep is sound or fitful. The effect of this gene has been demonstrated in fruit flies, mice, and humans.
'Sleep must be serving some important function,' said Dr Jason Gerstner of Washington State University and lead author of the study, published in Science Advances. 'But as scientists we still don't understand what that is. One way to get closer to that is by understanding how it is regulated or what processes exist that are shared across species.'
Dr Gerstner had previously identified FABP7 as one of the genes which change in expression over the sleep-wake cycle. Mice that were genetically engineered to have no FABP7 gene slept fitfully, compared to normal mice. This implied that mammals need FABP7 to sleep normally.
In collaboration with scientists in Japan, the team examined genetic data from nearly 300 Japanese men who had undergone a seven day sleep study. Of the participants, 29 shared a particular FABP7 variant and tended to sleep fitfully.
The researchers also tested the effect of FABP7 in fruitflies. They created fruitflies with mutated and normal FABP7 genes into astrocyte glial cells. Glial cells are found in the brain, where they support the activity of neurons and release neurotransmitters. Fruitflies with mutated FABP7 cells also slept fitfully.
'This suggests that there's some underlying mechanism in astrocytes throughout all these species that regulates consolidated sleep,' said Dr Gerstner. 'It's the first time we've really gained insight into a particular cell's and molecular pathway's role in complex behaviour across such diverse species.'
The researchers emphasise that other genes are almost certainly involved in the process of sleep. They say they intend next to investigate the relationship between sleep and functions such as neuronal activity, energy use, and memory and learning.