The coronavirus evolves

摘要

THE rise and spread of new variants of the coronavirus are seen as ushering in a dangerous new phase of the covid-19 pandemic. But from the virus's perspective, nothing has changed. It is just doing what comes naturally to viruses: evolving. It is now well-established that SARS-C0V-2 is a coronavirus with a large and unusually stable RNA genome, but that doesn't mean it doesn't change at all. Unlike most other RNA viruses, which are among the most mutation-prone biological entities in the world, SARS-CoV-2's genome changes very slowly. This is largely because it has a proofreading function that is efficient at eliminating errors during replication, a major source of the genetic variation that we call evolution.