ANYONE who supposes that evolution doesn't happen, or doesn't matter, should spare a thought for H5N1, the virus causing avian flu. If we're unlucky, this virus will give us a nasty demonstration of evolution in action...At the moment, the virus cannot pass easily from one person to another. But there are a couple of ways it could evolve to do so. The virus might infect someone already sick with a strain of human flu, and the two viruses could have sex, thus creating a new virus that contains some genes from each. Such viral hanky-panky is thought to have led...
