Stresses and strains: the evolution of Covid is not random

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Matt Ridley has narrated this article for you to listen to.

In the genetic diaspora of an epidemic, there is ferocious competition between strains of virus to get to the next victim first. That leads to apparently purposeful outcomes, as if the virus had a mind. One of the things people find hardest to grasp about evolution is that it appears purposeful but the mutations on which it feeds are random. How come dolphins evolved to swim if all they had to work with were random changes in genes? Viruses also mutate at random — but most people talk as though the rise and fall of these mutant versions is mainly down to chance or luck. It’s not.

Mutations occur all the time in RNA viruses; what matters is which ones find favour in natural selection. The champions of ‘Darwinian medicine’ have been calling for their colleagues to take evolution and adaptation more into account for years, and one of them, Paul Ewald of the University of Louisville, has something very relevant to say about this pandemic.