Friday, July 29, 2011

Extraterrestrial Life, How to Spot it, Is it Here on Earth, Can it be Made on Earth

‘It’s Alive! It’s Alive!’ Maybe Right Here on Earth


Life out there, Eden in a test tube


SAN DIEGO — Here in a laboratory perched on the edge of the continent, researchers are trying to construct Life As We Don’t Know It in a thimbleful of liquid.

Generations of scientists, children and science fiction fans have grown up presuming that humanity’s first encounter with alien life will happen in a red sand dune on Mars, or in an enigmatic radio signal from some obscure star.

But it could soon happen right here onEarth, according to a handful of chemists and biologists who are using the tools of modern genetics to try to generate the Frankensteinian spark that will jump the gap separating the inanimate and the animate. The day is coming, they say, when chemicals in a test tube will come to life.

By some measures, Gerald F. Joyce, a professor at the Scripps Research Institute here, has already crossed that line, although he would be the first to say he has not — yet.

Biologists do not agree on what the definition of life should be or whether it is even useful to have one. But most do agree that the ability to evolve and adapt is fundamental to life. And they also agree that having a second example of life could provide insight to how it began and how special life is or is not in the universe, as well as a clue for how to recognize life if and when we do stumble upon it out there among the stars.

“Everything we know about life is based on studies of life on Earth,” said Chris McKay, a researcher at NASA’s Ames Research Laboratory in Mountain View, Calif.

Dr. Joyce said recently: “It drives me crazy when astronomers say, ‘Surely the universe is pregnant with life.’ If we have an Earthlike planet, what are the chances of life arising? Is it one in a million? Is it one in two? I don’t see how you can say.”

He continued, “If you had a second example of life, even if it were synthetic, you might know better. I’m betting we’re just going to make it.”

Four years ago Dr. Joyce and a graduate student, Tracey A. Lincoln, now a researcher at the University of Massachusetts Medical School, evolved a molecule in a test tube that could replicate and evolve all by itself, swapping little jerry-built genes in a test tube forever, as long as it was supplied with the right carefully engineered ingredients.



An article in the Joyce Laboratory newsletter called it “The Immortal Molecule.” Dr. Joyce’s molecule is a form of RNA, or ribonucleic acid, which plays Robin to DNA’s Batman in Life As We Do Know It, assembling proteins in accordance with the blueprint encoded in DNA. Neither RNA nor DNA is alive by itself, any more than any other chemical, like bleach, or a protein. But in Dr. Joyce’s test tube, his specially engineered RNA molecule comes close, copying itself over and over, and evolving.

But, Dr. Joyce says, “We really would hope for more from our molecules than just replicating.”

Reproduction is the job of any life, he explained, but Earthly organisms have evolved a spectacular set of tricks to improve the odds of success — everything from peacock feathers to whale songs. Dr. Joyce’s molecules have not yet surprised him by striking out on their own to invent the molecular equivalent of writing a hit pop song.

It is only a matter of time, he said, before they do.

“Our job is to give them the running room to do that,” Dr. Joyce said.

The deeper philosophical and intellectual ramifications of test tube life are as enormous as they are unknown. The achievement would probably not come with sci-fi drama, say scientists who are squeamish about such matters anyway, saying such speculation is beyond their pay grade. No microbe is going to leap out of the Petri dish and call home, or turn the graduate students into zombies. Indeed, given the human penchant for argument and scientists’ habit of understatement, it could be years before everybody agrees it has been done.
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