FORGET survival of the fittest. For viruses, the winning mantra may be closer to survival of the sloppiest. An experiment with polio viruses suggests that being too good at copying genes can be a pathogen’s undoing.
Viruses that carry their genes as RNA rather than DNA have no equipment for proof-reading their genome when it is copied. The RNA polymerase enzymes that do the copying make mistakes, so whenever they infect an organism and replicate, they also produce a swarm of mutant virus particles.
Virologists suggested in the 1990s that instead of being a burden, this swarm of “quasi-species” might…
