Evolution of coronavirus SARS-CoV-2

A team of scientists studying the origin of SARS-CoV-2, the virus that has caused the COVID-19 pandemic, found that it was especially well-suited to jump from animals to humans by shapeshifting as it gained the ability to infect human cells.

Conducting a genetic analysis, researchers from Duke University, Los Alamos National Laboratory, the University of Texas at El Paso and New York University confirmed that the closest relative of the virus was a coronavirus that infects bats. But that virus's ability to infect humans was gained through exchanging a critical gene fragment from a coronavirus that infects a scaly mammal called a pangolin, which made it possible for the virus to infect humans.

The researchers report that this jump from species-to-species was the result of the virus's ability to bind to host cells through alterations in its genetic material. By analogy, it is as if the virus retooled the key that enables it to unlock a host cell's door -- in this case a human cell. In the case of SARS-CoV-2, the "key" is a spike protein found on the surface of the virus. Coronaviruses use this protein to attach to cells and infect them.

Very much like the original SARS that jumped from bats to civets, or MERS that went from bats to dromedary camels, and then to humans, the progenitor of this pandemic coronavirus underwent evolutionary changes in its genetic material that enabled it to eventually infect humans.

The researchers said tracing the virus's evolutionary pathway will help deter future pandemics arising from the virus and possibly guide vaccine research. The researchers found that typical pangolin coronaviruses are too different from SARS-CoV-2 for them to have directly caused the human pandemic.

See:

Xiaojun Li, Elena E. Giorgi, Manukumar Honnayakanahalli Marichannegowda, Brian Foley, Chuan Xiao, Xiang-Peng Kong, Yue Chen, S. Gnanakaran, Bette Korber, Feng Gao. Emergence of SARS-CoV-2 through recombination and strong purifying selection. Science Advances, May 29, 2020: eabb9153 DOI: 10.1126/sciadv.abb9153

 Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)