Evolutionary dynamics of SARS-CoV-2 during long-term serial passaging
Studies in vitro using serial passaging offer a controlled environment to investigate the emergence and persistence of genetic variants that may confer a selective advantage. We conducted long-term serial passaging in Vero E6 cells of a range of SARS-CoV-2 isolates to examine evolutionary dynamics and identify key mutations with implications for viral fitness, transmissibility, and immune evasion. Nine viral lineages, including four "variants of concern" and three former "variants under investigation" as designated by the World Health Organisation were chosen to investigate intra- and inter-lineage differences in evolution. Whole-genome sequencing (WGS) of viruses sampled over at least 33 passages (range 33-100) was analysed to determine the genetic variations compared with the SARS-CoV-2 reference genome.