SARS-CoV-2 Evolution: Addition by Subtraction

SARS-CoV-2 is an emergent virus. Specifically how it will adapt to human hosts and populations with growing immunity is unknown. Coronaviruses acquire substitutions more slowly than other RNA viruses due to a proofreading RNA-dependent RNA polymerase. In the spike glycoprotein, we find that deletions contribute to the evolution of antigenic novelty. Deletion variants arise in diverse genetic and geographic backgrounds, transmit efficiently, and are present in novel lineages, including variants of concern. By altering entire stretches of amino acids, deletions appear to accelerate SARS-CoV-2 antigenic evolution and may, more generally, drive adaptive evolution. 

Learning Objectives:
 
1. Define mechanisms for SARS-CoV-2 evolution 

2. Explain the impact of recurring SARS-CoV-2 mutations on protective antibodies