Research on coronavirus has been expanding to great levels now. Scientists are still wrapping their heads around the exponential increase in the pandemic, a virus that had been side-lined in Biology books until just decades back.
Let’s take a look at the history and the evolution of the deadly Coronavirus.
HOW DID CORONAVIRUS EVOLVE?
The Coronaviruses are a group of viruses using RNA as their genetic material and not the more prevalent DNA on earth. However, what makes them unique is that they have the largest of all RNA virus genomes.
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The first instances of the Coronavirus appearing were in the form of the Severe Acute Respiratory Syndrome (SARS) and the Middle East Respiratory Syndrome (MERS) emerging in 2002 and 2012.
The SARS-CoV caused the SARS outbreak. That emerged from the bats and went on to the civet cats and then to the humans. On the other hand, the MERS virus jumped from the camels to humans.
The current COVID-19 outbreak is also suspected to have emerged from bats. However, if it directly went on to humans and if there was an intermediate animal involved is still a matter of question. The current virus has since been named SARS-CoV-2. The genetic material of this virus is 70% similar to SARS CoV.
Even though the SARS-CoV 2 has milder symptoms, the 30% difference is what makes it so much more dangerous.
HOW DOES THE VIRUS FUNCTION?
Viruses necessarily need a receptor protein, which is a biochemical compound on a cell that they can use to enter the cell. Hence, they have a complementary viral protein on their surface that binds to the cell’s receptor protein and enters the body of the host organism. After reaching inside, the viruses hijack the cell’s resources to make new viruses.
The complementary viral protein of coronaviruses is called the spike protein and are visible as the pillar-like projections on the virus’s surface. They are named so as they are distinguished by the high number of spike-like proteins. The SARS-CoV and SARS-CoV-2 viruses both use the same protein, called angiotensin-converting enzyme 2 (ACE2). Any cell that makes the ACE2 protein can be infected by both the viruses. This includes all cells of the human respiratory tract.
However, research has shown that the SARS-CoV-2 spike protein binds strongly to the human ACE2 protein. Even more so than the SARS-CoV spike protein. Additionally, the new virus’s spike also has a target site for another human protein called furin. This protein is made in nearly all cells of the body. This furin-dependent activation is another property absent in the old SARS virus.
Thus, coronavirus remains one of the greatest pandemics to deal with yet.