Structural and Phylogenetic Analysis of SARS-CoV-2 Spike Glycoprotein from the Most Widespread Variants

The SARS-CoV-2 pandemic, reported for the first time at the end of 2019 in the city ofWuhan (China), has spread worldwide in three years; it lead to the infection of more than 500 millionpeople and about six million dead. SARS-CoV-2 has proved to be very dangerous for human health.Therefore, several efforts have been made in studying this virus. In a short time, about one year, themechanisms of SARS-CoV-2 infection and duplication and its physiological effect on human havebeen pointed out. Moreover, different vaccines against it have been developed and commercialized.To date, more than 11 billion doses have been inoculated all over the world. Since the beginning ofthe pandemic, SARS-CoV-2 has evolved; it has done so by accumulating mutations in the genome,generating new virus versions showing different characteristics, and which have replaced the preexisting variants. In general, it has been observed that the new variants show an increased infectivityand cause milder symptoms. The latest isolated Omicron variants contain more than 50 mutations inthe whole genome and show an infectivity 10-folds higher compared to the wild-type strain. Here,we analyse the SARS-CoV-2 variants from a phylogenetic point of view and hypothesize a futurescenario for SARS-CoV-2, by following its evolution to date.