WASHINGTON, Aug. 22, 1996 (UPI) -- A team of DNA hunters has deciphered the genetic code for a tiny methane-producing creature that thrives in sulfurous, near-boiling waters at thermal vents on the bottom of the sea, scientists said Thursday.
Investigators said this is the first time they have unraveled the genetic code for any member of the controversial third class of life on Earth, called Archaea, which were discovered in just the last 20 years.
Knowing the genetic code for a creature so different from the other two groups of life forms -- the bacteria and the higher organisms -- will shift the direction of the search for extraterrestrials, scientists said.
"If there was ever a candidate for something that sounds like it came from outer space and started life here, this would be compatible with that," said J. Craig Venter, the pioneering gene prospector who runs The Institute for Genomic Research (TIGR) in Rockville, Maryland. The TIGR lab led the investigation.
"It tells us things about life on this planet that would have seemed like science fiction even a few years ago," said Venter.
About two-thirds of the microbe's 1,738 genes are "new genes, completely unknown to biologists," said Venter. Oxygen, he said, is toxic to the microbe, called Methanococcus jannaschii, and it lives at the crushingly high pressures about a mile and a half (2.4 kilometers) below the ocean surface.
Holger Jannasch, from the Woods Hole Oceanographic Institution and the scientist for whom the microbe was named, found it in 1982 at a "white smoker" in the Pacific Ocean, living at pressures that could crush a submarine. His group retrieved samples using a specially designed research vehicle.
M. jannaschii's unique properties, such as its ability to gobble up carbon dioxide, nitrogen and hydrogen and spit out methane, might give it value in industry, said Venter. Some of the potential uses include the development of biological cars, new power sources, hazardous waste clean-ups and detergents.
Venter led the team of 40 scientists in the 18-month DNA analysis, which he likened to assembling a "jigsaw puzzle with about 40,000 pieces." The findings are published in the journal Science, and the genetic information will be posted on the TIGR site on the Internet .
Researchers said that the discovery of M. jannaschii's DNA code confirms the existence of a new class of life -- the Archaea. This newly described class, which only caught the eye of biologists in the mid-1970s and has generated controversy ever since, falls somewhere between the first class, bacteria, and the second class, which includes everything else from plants to humans.
"This is, in effect, a scientific dream come true," said Carl Woese, the evolutionary biologist at the University of Illinois, Urbana, who first proposed the idea of a third class of life about 20 years ago.
"This theory (of a third class of life) was given a universal thumbs down when it was first published," he said at a press conference.
Scientists now estimate that Archaea represent about half the biomass of the planet, which consists of the total weight of all microbes, plants and animals on Earth.
So little is known about the Archaea that they are rarely mentioned in graduate level textbooks, said Venter.
As for the role that M. jannaschii plays in the search for extraterrestrial life, Venter pointed out that the first Mars probes were launched in the late 1970s, before the Archaea were discovered. NASA is said to be laying plans to look for these kinds of organisms.
"We can't look for life on other planets if we don't understand life on this planet," he said. "This gives us a much better chance of finding life in other parts of the Universe."
Original file name: CNI - Archaea
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