The creation of life in the laboratory has moved two steps closer to reality in experiments designed to simulate the primitive conditions on Earth when life arose, American and Japanese scientists have reported to an international meeting of chemists.
The scientists also suggested that those same conditions still may exist deep in the ocean, where plumes of hot water and dissolved chemicals spew forth.
Even now, they said, new life may be forming around these "hydrothermal vents." This view is a reversal of the once-prevalent opinion that conditions favoring the origin of life have long since disappeared.
Another scientist attending the meeting said the new experiments, coupled with previous discoveries, "makes it look very much as if there is a certain inevitability to the origin of life."
The findings were described here at the International Chemical Congress of Pacific Basin Societies, which last week drew 4,000 scientists from 45 countries bordering the Pacific Ocean.
Laboratory attempts to simulate conditions under which life might arise began in the 1950s with the now-classic experiment in which electric sparks, portraying lightning, were discharged in a container of gases typical of the Earth's primordial atmosphere. Some of the gas molecules recombined to form amino acids, the building blocks of proteins.
Since proteins are one of the two kinds of molecules characteristic of living cells, the experiment supported the view that life could have arisen spontaneously under natural conditions on Earth.
In the ensuing decades, some scientists objected to the theory, pointing out that no one had yet demonstrated that the other molecule -- nucleic acids that make up DNA and RNA -- could be synthesized spontaneously. DNA is the stuff of genes, which carry a cell's genetic blueprints. RNA, a similar molecule, copies the DNA message and transmits it to the working machinery of the cell.
"I can report to you now that this has been achieved," said Cyril Ponnamperuma of the Laboratory of Chemical Evolution at the University of Maryland.
Ponnamperuma said he has succeeded in producing the building blocks of DNA and RNA by passing sparks through a mixture of gases like those used in the early experiments. These building blocks include the four kinds of "bases" in DNA -- adenine, guanine, thymine and cytosine -- and the fifth one -- uracil -- that substitutes for thymine in RNA.
He said that in the experiment the bases were even linked to the same kind of sugar molecules that form part of the so-called backbone of both DNA and RNA molecules. The same experiment also yielded the familiar mix of amino acids that make up proteins.
Ponnamperuma said the new discovery was the result not of any change in the experiment but of better methods of detecting small quantities of the substances. Apparently, the five bases had been forming all along.
The detection methods were ones that Ponnamperuma had developed to examine meteorites for signs of similar molecules. It had long been known that certain meteorites contain organic molecules, including amino acids. Now, he reported, a meteorite also has yielded all five nucleic acid bases.
Because this meteorite, which fell on Australia in 1969, is known to have formed some 4.5 billion years ago, at about the same time the Earth formed, it indicates that these molecules can and did arise under lifeless conditions.
The second step toward creating life in the lab was reported by Hiroshi Yanagawa of Japan's Mitsubishi-Kasei Institute of Life Sciences in Tokyo.
Like Ponnamperuma, Yanagawa has extended methods that were developed decades ago. In this case, it is the scientifically well-known finding that if dry amino acids are heated, they will link up into chains that resemble protein molecules. If some of the molecules are put in water, they will assemble into tiny, hollow spheres about the size of bacterial cells.
Although these microspheres are not alive, they represent the kind of architectural innovation that must have arisen at the dawn of life to enclose the kinds of nucleic acids that Ponnamperuma synthesizes in his lab.
Yanagawa reported that he has produced the protein-like spheres in a simulated seawater environment at temperatures and pressures comparable to those near the vents, where the water is more than 450 degrees F. and the pressure is 130 times that of sea level. (As in a pressure cooker, water under such pressures will not boil at those temperatures.)
Yanagawa said this suggests that life may have arisen not in the "warm, little pond" that Charles Darwin imagined, but under far more hellish conditions.
Ponnamperuma then suggested that a search should be made around the hydrothermal vents to see whether, even now, life is being created.
"All of this work, as well as our own, makes it look very much as if there is a certain inevitability to the origin of life," said Ronald Brown of Australia's Monash University.
Brown is a leader in the effort to detect organic molecules among the vast clouds of dust drifting in space.
"Wherever the conditions are right -- deep in the ocean or off in outer space -- the molecules of life assemble themselves," Brown said. "It does look as if life was no spectacular miracle."