SARS-CoV-2: Zoonotic origin of pandemic coronavirus.

A novel disease, of unknown origin, causing a deadly pneumonia of human patients was reported in December 2019 in Wuhan, Hubei province of China. Later called coronavirus disease (COVID-19), it rapidly spread across China and worldwide. Intensive research revealed that the etiological agent of the global COVID-19 pandemic was a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 genome contains typical coronavirus genes but the receptor binding domain (RBD) in the S protein is highly specific. The site for furin-like protease cleavage of the S protein into S1 and S2 subunits is also unique. Further analyses suggested that SARS-CoV-2 is of zoonotic origin. The analysis of the SARS-CoV-2 genome, especially the S gene, shows that natural evolutionary process between a bat-CoV and a pangolin-CoV or other animal coronavirus could have been important in creating SARS-CoV-2, with transmission of novel virus to the human population. On the other hand, new analyses indicate that SARS-CoV-2 is not a recombinant virus. Keywords: COVID-19; SARS-CoV-2; genome; bat coronavirus; pangolin coronavirus.