Advertisement
YOU ARE HERE: LAT HomeCollections

COLUMN ONE

Probing the Chemistry of Creation

Scientists are studying comets, volcanoes and other planets for clues to the origin of life on Earth. The quest is frustrating, but some say life forms may be brewed in a lab within decades.

May 15, 1997|ROBERT LEE HOTZ | TIMES SCIENCE WRITER

Come, take a seat in the kitchen of creation and try to replicate the lost recipe for the origin of life.

Be warned. This is a hypothetical dish that must be prepared through trial and error from the raw chemistry of Earth and space--without benefit of conventional biology or supernatural intervention.

So, experiment. Stoke the primordial planet's volcanic ovens. Stir its ocean caldron with wind. Boil it. Ice it. Season it with cyanide. Pepper the mix with comet dust and leaven it with time.

That is the task facing researchers trying to reconstruct the chemistry of creation.

To investigate the origin of life, some researchers are taking hints from the components of today's biochemistry and trying to work backward to discover simpler organic molecules that can perform life's essential functions.

In recent months, a NASA consortium of scientists has been shedding new light on the primeval biochemistry that existed before the first mating dance of proteins and DNA, which underlies all modern biology.

The group draws together biologists, chemists and geophysicists based at the research centers of "Biotech Beach" along the San Diego-La Jolla coastal corridor.

Its members have helped reset the clock of evolution and uncovered the earliest known evidence of life on Earth.

And in a crucial step with several other laboratories, other members have created a functional imitation of a primordial living molecule--a self-replicating substance that can be made to evolve and adapt without the help of DNA.

They have even evolved forms of DNA that nature did not. Last month two consortium scientists for the first time created a primitive molecule that can reproduce itself and evolve generation after generation in a continuous test-tube reaction. Some leading researchers now are confident that it may be only a decade or so before they can create life from scratch.

In the laboratory, however, life still requires a guiding hand.

Scientists have tried--and repeatedly failed--to create the conditions under which life can arise spontaneously. Nor have they been able to create a molecule that--unaided--can reproduce itself in a self-sustaining reaction. No one knows when anyone may achieve that ultimate goal.

This daunting laboratory enterprise, however, has become even more provocative as researchers eye primordial Mars and the frozen moons of Jupiter for havens of primitive life. Astronomers also yearn for signs of organic chemistry on any of the planets discovered recently around other sun-like stars.

Indeed, in some theoretical scenarios, the icy wastes of Jupiter's Europa, recently scanned by NASA's Galileo probe, bear a striking resemblance to the alien Earth of more than 4 billion years ago. Geologists suggest that life may exist in volcanic vents below Europa's icy crust, just as bacteria live in Earth's underwater volcanoes today and in lakes deep beneath the icecap of Antarctica.

The idea is seductive. Basic organic chemicals float in clouds of interstellar dust. They have been detected in the tails of comets like Hale-Bopp. And they have been discovered in meteorites as old as the solar system.

So it may seem only natural to expect that such interstellar chemicals seeded life on other planets. After all, life on Earth has taken up residence in so many unexpected places. Bacteria thrive in the absence of oxygen or sunlight, in boiling water, perpetual ice and subterranean depths, feeding readily on toxic wastes or on antibiotics designed to eradicate them.

But without a technical inkling of just how life arose in the one place it is known to exist, the search for life elsewhere in the universe is based largely on wishful thinking, researchers say.

More important for them, the effort to re-create the original chemistry of life offers the possibility of a scientific answer to one of humanity's most persistent spiritual and philosophical questions: How did life begin?

Despite the daunting uncertainties, a recent series of advances has many researchers hopeful that it may be only a matter of time before science succeeds in creating life in the lab.

"We may never know how it happened on Earth, but I am confident that somebody is going to do it in the laboratory within the next 10 or 20 years," said Leslie E. Orgel at the Salk Institute for Biological Studies.

Orgel, an authority on the origin of life, has joined with NASA and four other prominent specialists--Stanley Miller at UC San Diego, Gustav Arrhenius and Jeffrey L. Bada at the Scripps Institution of Oceanography, and Gerald Joyce at the Scripps Research Institute--to probe this enduring mystery.

Although they still may be far short of their goal, their growing understanding of life's early chemistry offers the promise of powerful new drugs based on molecules custom-tailored by directed test-tube evolution.

Advertisement
Los Angeles Times Articles
|
|
|