As an RNA virus, SARS-CoV-2's genome replication is innately error-prone such that mutations are expected (1). Every now and then, a mutation will provide an adaptive advantage (such as increased transmissibility or infectivity to a human host), and will be positively selected for in the population. This process drives viral genome evolution, and gives rise to the rich diversity of viral strains and lineages that we see. However, for SARS-CoV-2, the unexpected emergence of such diversity since late 2020 has led to considerable anxiety around the progression of disease, and the efficacy of diagnostics and vaccines to control its spread.