Craig Venter has not Demystified Life Yet

Craig Venter is a brilliant scientist, entrepreneur and showman. He excels at generating publicity for his achievements, whether the decoding of his own genome several years ago or his recent construction of a hybrid bacterium. In a typical Venter touch, the bacterium’s DNA contains base pairs that translate into portentous quotes, such as this one from the Irish novelist James Joyce: “To live, to err, to fall, to triumph, and to recreate life out of life.”

I don’t fault Venter for exaggerating the significance of his recent achievement, but I do fault others who should know better, such as the bioethicist Arthur Kaplan of the University of Pennsylvania. “What seemed to be an intractable puzzle, with significant religious overtones, has been solved,” Kaplan proclaims in Scientific American, adding that Venter and his colleagues have “created a novel lifeform from man-made parts.”

Actually, Venter has taken just another incremental step in the human manipulation of life, which began millennia ago when our ancestors started breeding dogs and ducks and accelerated recently as a result of advances in biotechnology. Venter’s team synthesized DNA from one type of bacterium, added modifications (like the Joyce quote) and inserted this genome into another bacterium whose own DNA had been extracted.

“The form of life that was created was not new,” Mark Bedau, a philosopher at Reed College and editor of the journal Artificial Life, says in Science. “What was essentially done was the re-creation of an existing bacterial form of life, except that it was given a prosthetic genome (synthesized in the laboratory), and except that the genome was put into the cytoplasm of a slightly different species.”

Scientists still have not come close to creating a living organism from non-biological materials, especially ones that might have existed on the earth 4 billion years ago. In other words, scientists have not shown how life began, how inanimate materials become animate.

This problem of life’s origin appears harder today than it did in 1953, when a 23-year-old graduate student named Stanley Miller filled a sealed glass apparatus with a few liters of methane, ammonia and hydrogen (representing the atmosphere) and some water (the oceans). A spark-discharge device zapped the gases with simulated lightning, while a heating coil kept the waters bubbling. Within a few days, the water and gases were stained with a reddish goo rich in amino acids, the building blocks of proteins. (Jeffrey Bada, a biochemist and former student of Miller, recently reanalyzed Miller’s old samples and discovered that they contain even more amino acids than Miller had realized.)

Miller and other scientists thought that they would quickly demonstrate in detail how genesis unfolded, but that hasn’t happened. When I interviewed Miller in the early 1990s, he admitted that the problem of life’s origin had turned out to be much harder than he had imagined. He was nonetheless still confident that one day scientists would crack the riddle of life’s origin: “It will be in the nature of something that will make you say, ‘How could you have overlooked this for so long?’ And everybody will be totally convinced.” Miller died three years ago, his dream unfulfilled.

There are now almost as many theories of life’s origin as there are theorists. The most popular is the “RNA world” theory, which posits ribonucleic acid as the first biomolecule. Whereas DNA cannot replicate without the help of enzymes, RNA can act as it own enzyme, snipping itself in two and splicing itself back together again. But RNA and its components are difficult to synthesize in a laboratory, let alone under conditions that might have prevailed on the new-born earth. Moreover, once RNA is synthesized, it can make new copies of itself only with a great deal of chemical coaxing by a scientist. Stanley Miller, among others, believed that some simpler--and possibly quite dissimilar--molecule must have paved the way for RNA, but no strong candidate has emerged.

Arthur Kaplan declares that Venter and other scientists have dispelled the notion that life “is sacred, special, ineffable and beyond human understanding.” Wrong. We still have no idea how life began, or whether life exists only here on our lonely planet or pervades the cosmos. One of the great ironies of modern science is that as we gain more power over life, it remains as fundamentally mysterious as ever.

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