Lab cracks genetic code of ancient organism Md. breakthrough may help explain evolution of life

August 23, 1996|By Mark Guidera | Mark Guidera,SUN STAFF

WASHINGTON -- A team of scientists headed by researchers at the Institute for Genomic Research in Rockville has cracked the genetic code for a tiny, ancient organism that thrives only in deep sea thermal vents, a breakthrough experts say should help decipher how life evolved on this planet.

"This is an exciting day," said Dr. Craig Venter, director of the institute, who headed the gene sequencing effort. "This isn't just any species. It's a very different life form."

The discovery and its findings, published today in the journal Science, also appear to have strong potential for commercial applications, such as renewable fuels for cars and homes and safer ways to clean up spoiled environments.

That's because the organism produces and recycles natural methane, a gas, and survives at very high temperatures and pressures, a requirement for many industrial processes today.

Richard J. Roberts, a British scientist who won the Nobel Prize for biology in 1993 for his work on genetic inheritance, called the breakthrough "very exciting for science and biology."

"We have known so very little about these organisms, yet they are very likely one of the oldest on the Earth," he said. "The applications for science and commerce are probably tremendous."

The tiny organism, about the size of some common bacteria, is part of what's known as the Archaea (pronounced are-kay) kingdom, a single-celled primitive life form discovered just 13 years ago. Scientists speculate Archaea may have ancestors that go back 3 billion years.

Evolutionary scientists have theorized that all of life sprang from one form, eventually dividing into two distinct kingdoms, Bacteria and Eucarya, which include multi-cell forms of life, such as humans, animals and plants, or "the visible world."

The scientific community, Roberts said, was excited that the team had discovered that the Archaea's gene sequence showed it has some genes with the same characteristics as bacteria and some that are similar to those of higher life forms.

But two-thirds of the genes, Venter said, are "completely different than anything else ever seen before."

"They are totally new to biology and science."

That information, he said, confirmed what some scientists have suspected: that Archaea constitute their own distinct kingdom.

The genome -- the instructions for how life is to operate -- was that of a microscopic organism named Methanococcus jannaschii. It was mapped by a team that included researchers at Johns Hopkins University and the University of Illinois.

Its name is derived, in part, from the man who first found the organisms 13 years ago, Dr. Holger Jannasch of the Woods Hole Oceanographic Institution.

Archaea have long puzzled the few scientists who study them because they have an affinity for extremely hostile environments.

Researchers used a deep submergence vehicle from the Woods Hole Oceanographic Institution to get samples. The organisms were plucked from one of the most remote places on Earth, thermal vents found two miles down and 100 miles off the coast of Mexico.

The area around these undersea volcanoes has temperatures of about 200 degrees Fahrenheit and atmospheric pressures 200 times greater than that of the air we breathe -- enough to crush an ordinary submarine. Also, there is no sunlight and no oxygen.

The organism makes everything it needs to grow and live from the elements surrounding it, carbon dioxide and hydrogen.

It is these attributes -- the ability to sustain high temperatures and pressures and no need for oxygen -- that have interested the Department of Energy, said Charles Curtis, the agency's deputy secretary.

"These microorganisms could help us solve some important problems," said Curtis, such as developing environmentally safe substances to help clean up toxic waste sites.

Archaea, said Venter, appear to have some ability to bind to heavy metals, a characteristic that might help in toxic cleanup efforts. And they might help scientists develop cheap, environmentally friendly energy sources from their methane-producing trait.

"We're just at the threshold of understanding just what applications this discovery might have," Curtis said.

Human Genome Sciences Inc., a Rockville-based biotechnology company that funds the Institute for Genomic Research, a nonprofit venture, will hold the rights to sell or commercialize the discovery, Venter said.

But it's not the commercial applications that have the science community buzzing right now.

Hamilton O. Smith, a Nobel Prize laureate and professor of molecular biology and genetics at Johns Hopkins University Medical School, said the genetic information culled from the project is disrupting more than a few theories about what conditions are needed to sustain life.

"If someone had told me 10 years ago that such an organism existed, I would have said it's impossible," said Smith, who helped Venter's team on the project.

"From an evolutionary standpoint, we're looking at an organism that has evolved over millions of years, yet lives in an extreme niche of the Earth that is probably not unlike what the Earth looked like when it was first formed."

Roberts said the gene sequence should help scientists in the quest to determine how life started on Earth. "Life, in fact, probably evolved in the early days around these hot undersea vents," said Roberts, who heads his own biotechnology company, New England Biolabs.

"The guy on the street might not find all this interesting today," he said. "But in the future it could have a very big impact on how we live and think of life here on Earth."

Pub Date: 8/23/96

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