Viewpoint: Origin of SARS-CoV-2

• Main Authors: Kenneth Lundstrom, Murat Seyran, Damiano Pizzol, Parise Adadi, Tarek Mohamed Abd El-Aziz, Sk. Sarif Hassan, Antonio Soares, Ramesh Kandimalla, Murtaza M. Tambuwala, Alaa A. A. Aljabali, Gajendra Kumar Azad, Pabitra Pal Choudhury, Vladimir N. Uversky, Samendra P. Sherchan, Bruce D. Uhal, Nima Rezaei, Adam M. Brufsky
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Viruses
• Subjects: coronavirus; COVID-19 pandemic; origin of SARS-CoV-2; receptor binding domain; genome homology; natural selection
• Online Access: https://www.mdpi.com/1999-4915/12/11/1203

The origin of the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) virus causing the COVID-19 pandemic has not yet been fully determined. Despite the consensus about the SARS-CoV-2 origin from bat CoV RaTG13, discrepancy to host tropism to other human Coronaviruses exist. SARS-CoV-2 also possesses some differences in its S protein receptor-binding domain, glycan-binding N-terminal domain and the surface of the sialic acid-binding domain. Despite similarities based on cryo-EM and biochemical studies, the SARS-CoV-2 shows higher stability and binding affinity to the ACE2 receptor. The SARS-CoV-2 does not appear to present a mutational “hot spot” as only the D614G mutation has been identified from clinical isolates. As laboratory manipulation is highly unlikely for the origin of SARS-CoV-2, the current possibilities comprise either natural selection in animal host before zoonotic transfer or natural selection in humans following zoonotic transfer. In the former case, despite SARS-CoV-2 and bat RaTG13 showing 96% identity some pangolin Coronaviruses exhibit very high similarity to particularly the receptor-binding domain of SARS-CoV-2. In the latter case, it can be hypothesized that the SARS-CoV-2 genome has adapted during human-to-human transmission and based on available data, the isolated SARS-CoV-2 genomes derive from a common origin. Before the origin of SARS-CoV-2 can be confirmed additional research is required