The pathogenesis of poliovirus relies on virus diversity per se, not the selection of any particular adaptive mutation, say Marco Vignuzzi, Raul Andino (UCSF, San Francisco, CA), and colleagues. Different variants may achieve different tasks in a group effort to navigate the host environment.
This is how a quasispecies, or group of variants, is meant to behave, based on theory and mathematical modeling. “But really this is the first study that provides experimental evidence,” says Andino.
Andino had previously used a mutagen to push viruses into evolutionary oblivion; he now uses a mutant that survives this treatment because of a less error-prone polymerase.
These G64S viruses generated far fewer chemical-resistant variants and responded poorly to a challenge with this antiviral drug. But G64S was also far less potent in mice: it had to be given in a 300-fold higher dose to cause 50% lethality, and...
