How does the virus evolve?
It is extremely difficult to predict mutations of the virus, since the first infections scientists
Does the virus have several types? What kind?
Scientists have several points to answer this question.vision. For example, Chinese biologists said in early March that the virus could be divided into two subtypes - S and L. One of them will differ in acute symptoms during infection and can also spread faster. Not everyone supported this idea. An alternative view is that changes in the virus genome could be caused by various random processes, rather than real differences in the infectivity of these subtypes of SARS-CoV-2.
A month ago, molecular biologists analyzedgenomes of several thousand strains of SARS-CoV-2 and came to the conclusion that the virus was divided into three separate lineages, each of which had its own set of mutations in key genes.
Which of these species predominates?
According to scientists from New York University,Among the total mass of COVID-19 strains, about 70% have a common mutation in the S gene. This gene controls the production of proteins in that part of the SARS-CoV-2 envelope that is directly related to its penetration into the body.
And where is the new version of the virus?
A new version of the virus was discovered recently. Judging by its rapid spread, this is the D614G mutation. It not only helps the virus to enter the body, but also accelerates its spread between the most different types of human cells. The lungs, liver and intestines are most seriously affected. There is another suggestion why the new type of virus is so infectious - the cells of the virus are more resistant to immunity.
The fact is that D614G is almost always foundtogether with another mutation, P314L. In turn, it changes the way ORF1b works. And it is critically important in the copying of the RNA of the virus and its reproduction inside the infected cells.
What affects the new type of virus?
To conduct experiments on a new type of virus, the groupScientists made “dummies” of the coronavirus from some components of its shell; they also contained a luminous protein. After that, scientists monitored how actively they penetrate into those tissues of the human body that are affected by the coronavirus. As a result, the number of luminous intestinal cells increased by 2.5 times, in the lungs by five times, and in the liver by almost eight times.
In addition, enzymes of the innate immune systemhumans destroyed the coat proteins of this version of SARS-CoV-2 more slowly than other varieties of the virus. This means that the mutation reduced the immunity's chance of recognizing the D614G virus. Also, enzymes of the immune system destroyed the shells of the mutated version of the coronavirus much more slowly. As a result, thanks to the D614G mutation, a new infectious type of coronavirus has become dominant in such a short time.