Making viruses the natural way

When it comes to viruses, we humans like to pretend we know much more than we really do. It's understandable. The influenza virus, for example, has only ten genes. It is just a shell that delivers genes and proteins into a host cell, where it hacks the biochemistry to manufacture more viruses. It seems like such an easy biological problem to solve.

Yet the flu and other viruses hide a complexity which virologists have only partly uncovered. The idea that someone could intentionally design a super-lethal virus from scatch–as plausible as it may seem–is, for now, a delusion.

If you've been following the news this past week, you may think I've just been proven wrong. Reports have surfaced about two teams of scientists producing flu viruses that could potentially kill millions if they escaped from the labs. The scientists have the viruses locked up tight for now, and government officials are debating whether they can publish their results. (New Scientist and Science have excellent reports.)

So is this evidence that scientists have become viral Frankensteins, who can engineer pathogens at will? Hardly.

The new research is part of a long-running struggle to understand how new ...