The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a challenge for long-term public health efforts to minimize the effects of coronavirus disease 2019. Whole-genome sequencing of outbreak cases has enabled global contact tracing efforts and the identification of mutations of concern within the virus’ genome. However, complementary approaches are necessary to inform our understanding of virus evolution and clinical outcomes. Here, we charted the evolution of the virus within a controlled cell culture environment, focusing on nine different virus lineages.

Our approach demonstrates how SARS-CoV-2 continues to evolve readily in vitro, with changes mirroring those seen in outbreak cases globally. Findings of the study are important for (i) investigating the mechanisms of how mutations arise, (ii) predicting the future evolutionary trajectory of SARS-CoV-2, and (iii) informing treatment and prevention design.