ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has experienced considerable adaptive evolution after being detected in December 2019 in Wuhan, China, resulting in the emergence of multiple variants harboring mutations with phenotypic implications. These variants continue to astound us with their enhanced transmissibility, disease severity, and capacity to evade post-immunization sera or therapeutic antibodies. This chapter examines several zoonotic evidence, including comparative genomics with other related coronaviruses, molecular footprints, and epidemiological data. We also outlined the evolution of multiple mutations in various SARS-CoV-2 variants of concern (VOCs) and discussed the functional implications of those mutations in terms of altered binding affinity to human angiotensin-converting enzyme 2 receptor (ACE2) receptor, enhanced transmissibility and virulence, broadened host range, and reduced neutralization to currently available vaccines and therapeutic antibodies. Altogether, close monitoring of SARS-CoV-2 variants in humans 2and animals is necessary to better understand the complex evolutionary dynamics, spillover events, and efficacy of currently approved vaccines and therapeutics against emerging variants, which will ultimately assist in the design of effective mitigation strategies for emerging SARS-CoV-2 variants.
