Building Artificial Viruses

In the past five years, new technology has made it easier to genetically modify microbes and even create new ones from scratch. Some worry that the developments could lead to novel and more dangerous kinds of bioterror threats.

"There's a name for fixed defenses that can easily be outflanked: They are called Maginot lines," said Roger Brent, a California molecular biologist and former biodefense adviser to the Defense Department, referring to the elaborate but short-sighted network of border fortifications built by France after World War I to prevent future invasions by Germany.

"By themselves," Brent said, "stockpiled defenses against specific threats will be no more effective to the defense of the United States than the Maginot line was to the defense of France in 1940."

How to Make a Virus

Wimmer's artificial virus looks and behaves like its natural cousin -- but with a far reduced ability to maim or kill -- and could be used to make a safer polio vaccine. But it was Wimmer's techniques, not his aims, that sparked controversy when news of his achievement hit the scientific journals.

As the creator of the world's first "de novo" virus -- a human virus, at that -- Wimmer came under attack from other scientists who said his experiment was a dangerous stunt. He was accused of giving ideas to terrorists, or, even worse, of inviting a backlash that could result in new laws restricting scientific freedom.

Wimmer counters that he didn't invent the technology that made his experiment possible. He only drew attention to it.

"To most scientists and lay people, the reality that viruses could be synthesized was surprising, if not shocking," he said. "We consider it imperative to inform society of this new reality, which bears far-reaching consequences."

One of the world's foremost experts on poliovirus, Wimmer has made de novo poliovirus six times since his groundbreaking experiment four years ago. Each time, the work is a little easier and faster.

New techniques developed by other scientists allow the creation of synthetic viruses in mere days, not weeks or months. Hardware unveiled last year by a Harvard genetics professor can churn out synthetic genes by the thousands, for a few pennies each.

But Wimmer continues to use methods available to any modestly funded university biology lab. He reckons that tens of thousands of scientists worldwide already are capable of doing what he does.

"Our paper was the starting point of the revolution," Wimmer said. "But eventually the process will become so automated even technicians can do it."

Wimmer's method starts with the virus's genetic blueprint, a code of instructions 7,441 characters long. Obtaining it is the easiest part: The entire code for poliovirus, and those for scores of other pathogens, is available for free on the Internet.

Armed with a printout of the code, Wimmer places an order with a U.S. company that manufactures custom-made snippets of DNA, called oglionucleotides. The DNA fragments arrive by mail in hundreds of tiny vials, enough to cover a lab table in one of Wimmer's three small research suites.