London, July 22 (IANS): Losing even one night of sleep can alter your genes, putting you at an increased risk of obesity and Type 2 diabetes, new research says.

Swedish researchers at Uppsala University and the Karolinska Institutet found that genes that control the biological clocks in cells throughout the body are altered even after one night of sleep loss.

Previous research has shown that our metabolism is negatively affected by sleep loss, which has been linked to an increased risk of obesity and type 2 diabetes.

"The results indicate that changes of our clock genes may be linked to negative effects (like obesity and Type 2 diabetes) caused by sleep loss", said Jonathan Cedernaes, lead author on the study and researcher at Uppsala University in Switzerland.

For the small yet significant study, the team studied 15 healthy normal-weight men who on two separate occasions came to the lab for almost two-night long stays.

During the second night, the participants slept as usual (over eight hours) in one of the two sessions while they were kept awake in the other of these sessions but in random order.

Molecular analyses of the collected tissue samples showed that the regulation and activity of clock genes was altered after one night of sleep loss.

The activity of genes is regulated by a mechanism called epigenetics. This involves chemical alterations to the DNA molecule such as methyl groups - a process called methylation - which regulates how the genes are switched on or off.

The researchers found that clock genes had increased numbers of such DNA marks after sleep loss.

They also found that the expression of the genes, which is indicative of how much of the genes' product is made, was altered.

"This study is the first to directly show that epigenetic changes can occur after sleep loss in humans, but also in these important tissues," said Cedernaes in a paper appeared in the Journal of Clinical Endocrinology and Metabolism.

This means that at least some types of sleep loss or extended wakefulness, as in shift work, could lead to changes in the genome of your tissues that can affect your metabolism for longer periods, authors said.