It has emerged that scientists are looking to a common zebrafish to learn how the human circadian system functions.
Circadian rhythms - the natural cycle that dictates our biological processes over a 24-hour day -control our sleep-wake process.
Disruptions in the cycle are also associated with depression, problems with weight control, jet lag and more.
They have discovered that a mechanism that regulates the circadian system in zebrafish also has a hand in running its human counterpart.
The zebrafish discovery provides an excellent model for research that may help to develop new treatments for human ailments such as mental illness, metabolic diseases or sleep disorders.
Previous research on zebrafish revealed that a gene called Period2, also present in humans, is associated with the fish's circadian system and is activated by light.
"When we knocked down the gene in our zebrafish models, the circadian system was lost," said Prof. Yoav Gothilf of Tel Aviv University's Department of Neurobiology at the George S. Wise Faculty of Life Sciences.
Gothilf's team subsequently identified a region called LRM (Light Responsive Model) within Period2 that explains how light triggered gene activity.
To determine whether a similar mechanism may exist in humans, Gothilf and his fellow researchers isolated and tested the human LRM and inserted it into zebrafish cells.
In these fish cells, the human LRM behaved in exactly the same way, activating Period2 when exposed to light - and unveiling a fascinating connection between humans and the two-inch-long fish.
The research appears in the journals PLoS Biology and FEBS Letters.