Navigation Links
Through evolution, cavefish have lost sleep

Cave life is known to favor the evolution of a variety of traits, including blindness and loss of eyes, loss of pigmentation, and changes in metabolism and feeding behavior. Now researchers reporting online on April 7 in Current Biology, a Cell Press publication, have added sleeplessness to that list.

"Cave-adapted fish sleep lessmuch lessthan closely related surface fish," said Richard Borowsky of New York University. "In some ways, their sleep phenotypes are similar to those of humans with sleep disorders."

The fish do sleep, but only for relatively short periods, Borowsky explained. Once they wake up, they remain active for a relatively long time. That sleep-and-wake cycle is repeated throughout the continued darkness of the cave.

The discovery was made by studying three cave populations of Mexican Blind Cave Fish (Astyanax mexicanus), a species ideal for such studies because it includes eyed surface and numerous blind cave populations. Although most of those cave populations have been founded independently by individuals living on the surface, they have nonetheless converged over the course of evolution on similar traits suitable to their new environments.

Borowsky and Erik Dubou, lead author of the study, got the idea that the transition from surface to cave might be associated with less sleep based on anecdotal, nighttime observations of fish in their laboratory. Their surface fish clearly sleep at night. They could be found inactive at the bottom of their tanks with fins drooping. The cavefish, on the other hand, actively patrol their laboratory homes through the wee hours.

To further study the basis of those behavioral differences, the researchers allowed surface and cave individuals to mate in the lab and studied their hybrid offspring. Those studies yielded evidence showing that cavefish differ from surface fish in sleep behavior because of a few dominant gene mutations that became fixed in the cave populations as they adapted to their new life.

"We have documented a cave-related phenotype unsuspected until now that might turn out to be the most basic adaptation of aquatic vertebrates to cave life," Borowsky said. His team plans to investigate further to parse out the evolutionary forces driving the convergence.

It remains to be tested, but Borowsky doesn't think the cavefish need less sleep, exactly. Rather, they may need to be awake more. "These fish live in an environment where food is generally scarce and episodically and unpredictably present," he said. "If you are asleep when a bit of food floats by, you are out of a meal and out of luck."

The discovery might offer clues to understanding variation in sleep among other species and even sleep disorders in humans. That's because the genes controlling sleep patterns in the fish are very likely to play the same roles in other animals.

"This study is the first step to identifying the responsible genes," he said.


Contact: Elisabeth Lyons
Cell Press

Related biology news :

1. Major breakthrough in preventing premature birth announced by NIH/WSU
2. From science fiction to research breakthrough
3. The way to (kill) a bugs heart is through its stomach
4. No scalpel: Minimally invasive breakthrough for men’s enlarged prostates improves symptoms
5. Breakthrough in Niemann-Pick Type C research reported by Notre Dame and Cornell scientists
6. San Diego Zoo Global joins effort to conserve the Amazonian rain forest through Peru field station
7. Researchers looking at a rare disease make breakthrough that could benefit everyone
8. Cancer breakthrough to prevent heart failure and increase survival rates
9. Breakthrough on cystic fibrosis 1 step closer as new research alliance formed
10. Biomedical breakthrough: Blood vessels for lab-grown tissues
11. 7 CAMH scientists win Young Investigator awards focused on breakthrough research
Post Your Comments:
(Date:6/21/2016)... British Columbia , June 21, 2016 /PRNewswire/ ... appointed to the new role of principal product ... been named the director of customer development. Both ... NuData,s chief technical officer. The moves reflect NuData,s ... teams in response to high customer demand and ...
(Date:6/16/2016)... 16, 2016 The global ... to reach USD 1.83 billion by 2024, according ... Inc. Technological proliferation and increasing demand in commercial ... to drive the market growth.      ... The development of advanced multimodal techniques for biometric ...
(Date:6/9/2016)... , June 9, 2016  Perkotek an innovation leader in attendance control systems ... seamlessly log work hours, for employers to make sure the right employees are actually ... ... ... ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , June 27, 2016  Sequenom, Inc. (NASDAQ: ... to enabling healthier lives through the development of innovative ... of the United States denied ... that the claims of Sequenom,s U.S. Patent No. 6,258,540 ... eligibility criteria established by the Supreme Court,s Mayo Collaborative ...
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , the leading software as ... Clinical Reach Virtual Patient Encounter CONSULT module which enables both audio and video ... trial team. , Using the CONSULT module, patients and physicians can schedule a face ...
(Date:6/27/2016)... ... 27, 2016 , ... Rolf K. Hoffmann, former senior vice ... University of North Carolina Kenan-Flagler Business School effective June 27. , ... with a focus on the school’s international efforts, leading classes and participating in ...
(Date:6/27/2016)... 27, 2016   Ginkgo Bioworks , a leading ... was today awarded as one of the World ... world,s most innovative companies. Ginkgo Bioworks is engineering ... real world in the nutrition, health and consumer ... with customers including Fortune 500 companies to design ...
Breaking Biology Technology: