The researchers examined dozens of coronaviruses
Microbiologists have built the tree of evolution of the closest relatives of the new type of coronavirus and has stated about a big possibility of a repeat of the pandemic.
Scientists have found that the ancestor of the virus SARS-CoV-2 separated from the common tree of evolution of viruses of bats of 40 to 70 years ago. This conclusion molecular biologists have come by comparing the genomes of several closest relatives of the coronavirus SARS-CoV-2. Their findings on Tuesday, 28 July, published the scientific journal Nature Microbiology.
“Our analysis shows that the viruses, the related SARS-CoV-2, circulate among podkovonos bats for many decades. These viruses are characterized by high versatility that can explain how there was an epidemic COVID-19 and how something similar could happen in the future,” the article says.
Microbiologists for a long time trying to figure out where and when there was a new type of coronavirus – the causative agent COVID-19, and then, when he started to spread from person to person. Epidemiologists have not yet come to a definite opinion about it.
In particular, biologists can’t yet say exactly where and when the virus, which animals were its intermediate carriers, and what role in its formation was played by the so-called recombination – exchange of genetic material between different types of coronaviruses.
By studying the genomes of six dozen of the closest modern relatives of SARS-CoV-2, a group of molecular biologists under the guidance of Professor University of Edinburgh (UK) David Robertson learned the history of the evolution of the ancestors of this virus.
To do this, scientists have developed special algorithms by which they deleted from the genomes of these pathogens all traces of recombination. It had to be done, because the exchange of fragments between RNA viruses interfere with the scientists to figure out the family ties between them and to determine the time of their appearance, as well as their rate of evolution.
Treating the genomes of all studied viruses in a similar way, scientists have built the tree of evolution closest relatives of SARS-CoV-2. After they tried to understand when he separated himself from the alleged ancestor of the virus RaTG13 that affects podkovonos bats that live in the South and South-East China.
These calculations confirmed that SARS-CoV-2 and RaTG13 actually related. However, the researchers found that their ancestors were divided unexpectedly long time: depending on the methods of analysis of the genome and the set of sites analysed RNA in 1948 or 1969. Later divided the ancestors of the pathogen COVID-19 and SARS SARS: between 1952 and 1970.
All this, as the researchers note, suggests that viruses similar to SARS-CoV-2, circulate among bats in southern China has more than half a century. Considering the special structure of their shell that allows them to adhere to receptors on the surface of lung cells of several mammalian species, it explains why human populations were two similar virus (SARS-CoV-1, the causative agent of SARS, and SARS-CoV-2, the causative agent COVID-19) and caused a serious outbreak of pulmonary infection.
Earlier, there is a new version of the origin of the coronavirus. British scientist expressed confidence that the virus SARS-CoV-2 there was always dormant.