Summary

The credible and detailed publications linked at the bottom of this page take the structure of SARS-CoV-2, and its unique characteristics which are uncommon in SARS-like viruses into consideration when theorizing its origin. They offer a new perspective to the nature of viral replication by using genomic data to emphasize variations that could have arisen as a result of natural selection and adaptation.

Scientists say that SARS-CoV-2 might have originated from a bat. However, an animal sold at the Wuhan seafood market might have been the intermediate host which passed the Coronavirus from bat to human (zoonotic transfer). Studies have proven that SARS-CoV-2 is not a result of a purposefully manipulated lab construct but rather a result of mutations in structure due to natural selection; this natural selection occurs either on a human or a human-like ACE2 receptor. Interestingly, though the RBD of COVID-19 binds to the ACE2 receptors with a much higher binding affinity than SARS-CoV, analysis predicts that this cannot occur in normal circumstances given that the interaction is not optimal/ideal. This is because the RBD sequence of COVID-19 is different from that of SARS-CoV. The mutated RBD, therefore, cannot bind without optimal conditions. This observation further supports the theory of natural selection either in a homologous animal host before zoonotic transfer or in a human after zoonotic transfer. There is also a theory that natural selection could have occurred during zoonotic transfer.

Sources (all of above information):

• The Lancet. "Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding," https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30251-8/fulltext#seccestitle10

• Andersen, K.G., Rambaut, A., Lipkin, W.I. et al. The proximal origin of SARS-CoV-2. Nat Med (2020). https://doi.org/10.1038/s41591-020-0820-9.