Swine Flu Is Evolution in Action, page 1

By Robert Roy Britt, Editorial Director

posted: 28 April 2009 01:30 pm ET

Anyone who thinks evolution is for the birds should not be afraid of swine flu. Because if there's no such thing as evolution, then there's no such thing as a new strain of swine flu infecting people.

For the rest of the population, concern is justified.

The rapid evolution of the influenza virus is an example of Nature at her most opportunistic. Viruses evolve by the same means as humans, plus they use tricks such as stealing genetic code from other viruses.

The strategy is what makes the flu so virulent and often keeps the microbes one step ahead of scientists who would destroy or neutralize them.

Pigs to you

While much of the modern controversy over evolution centers around whether humans evolved from non-human primates (scientists overwhelmingly agree this is the case), some people still try to poke holes in the theory of evolution, one of the most solid theories in science. In addition to evidence from ancient fossils and modern DNA studies, one of the many lines of evidence supporting evolution is that it can quite simply be seen in action among some species that evolve particularly rapidly, such as fruit flies.

But on no stage does evolution unfold more quickly or with more potentially sickening or lethal consequences for humans than among viruses. It is, to pass on a scary phrase used among scientists and marketers, viral evolution. And you could be the star host of this all-too-often deadly show.

The sudden ability of the new swine flu virus to hop from pigs to humans and then to skip from person to person, at least in Mexico, is an excellent example of evolution at work.

"Yes, this is definitely evolution," said Michael Deem, a bioengineer at Rice University in Texas.

Deem studies how evolution is affected not just by mutations but by the exchange of entire genes and sets of genes. Viruses, which are basically packets of DNA with a protein coat, are really good at this. Viruses are also really good at exploiting the fact that we humans cough and sneeze without covering ourselves and generally don't wash our hands frequently in a day.

"Viruses have evolved to exploit human contact as a way of spreading," points out Peter Daszak of the Wildlife Trust, whose team 14 months ago predicted just this sort of evolution in an animal flu, coming from Latin America to the United States after evolving to infect people.

David Schaffer, a professor of chemical engineering and bioengineering at the University of California at Berkeley, explains the mechanics of how a flu virus morphs:

"For flu, there are multiple ways that diversity can arise (the virus has multiple strands of RNA in its genome, and it can mix and swap strands with different flu variants to give rise to fully novel variants ... in addition, each strand can individually mutate)," Schaffer explained this week.

"Furthermore, in this case, the 'enhanced' property from the virus' point of view is the ability to infect humans. So, this is viral evolution."