Aired secret of coral mass wedding
Moonlight and an existing gene in humans provide synchronization
The "mass wedding" of coral found on hundreds of thousands of square kilometers of ocean exact place at the same time. Now scientists have figured out why: a particular gene allows the corals, the period after the moonlight to determine and thus to coordinate their reproduction. As they report in the journal "Science", still plays this gene in humans a role in the circadian clock.
The spawning of corals: Every year, shortly after a full moon, is one of the greatest mysteries of nature occurs. Million animals released then within a short time their eggs and sperm into the sea water - and this is hundreds of kilometers away at exactly the same time. In Australia's Great Barrier Reef, the largest continuous reef area of the Earth, will be held this event more than 350,000 square kilometers rather than distributed.
Sensor gene registered moonlight
As the tiny coral contrive the right time to determine as accurately, has been a mystery. Now, however, researchers have discovered from the ARC Centre of Excellence for Coral Reef Studies (CoECRS) in Australia a possible trigger. Previously water temperature, tides and weather conditions were discussed as factors influencing it. However, since the "mass wedding" always takes place shortly after a full moon, the scientists decided to investigate the light closer than factor.
In their experiments they put coral in the laboratory light of different colors and intensities, in addition they collected from the ocean corals of the genus Acropora at different times around the full moon a. The researchers analyzed the gene activity in the animals and soon came across a recurring pattern in the samples: During the full moon nights a gene called Cry2 has been particularly active. It is one of the cryptochromes, a group of genes that are also present in insects, fish, mammals and humans.
"In a sense, they are the forerunners of the eyes," says Professor Ove Hoegh-Guldberg of the University of Queensland. "That's the key for one of the central mysteries of coral reefs. We have always wondered at how the eyeless coral recognize the moonlight and it can determine the exact hour to spawn. "
Gen still active in humans
In humans the Cryptochrome form another part of the internal timer that synchronizes us with the rhythms of nature. Your ability to perceive light, but lost with us. "They play an important role in the internal clocks of many species of corals to fruit flies, zebrafish to mice," says Professor David Miller of CoECRS. "The proteins that they produce, which in humans and other mammals are very similar, although they are similar in their function more like those of fruit flies."
"We suspect that these genes were already in the Precambrian as light sensors in primitive forms of life, more than 500 million years ago," said Oren Levy, who headed the study. "The fact that they are connected to the system that repairs damage caused by UV radiation, suggests that they have evolved in eyeless organisms. This refuge during the day in front of the UV light in deep water, but they took advantage of the bluish light of the moon to synchronize their internal clocks and reproductive cycles. "
According to the researchers, the newly discovered genes of light corals are a renewed indication that people and corals are ultimately related to each other and also in front of hundreds of millions of years once had a common ancestor. However, whether these ancient genes may also be responsible for ensuring that some people are particularly prone during the full moon for romance, is not known. What is clear is that they are still part of our biological clock in every case.
(ARC Centre of Excellence in Coral Reef Studies, 23.10.2007 - NPO)
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