Scientists Have Discovered The Closest Relative Of SARS-CoV-2 In Bats

Scientists have discovered the closest relative of SARS-CoV-2 in bats

According to Chinese and Australian researchers, this discovery should put an end to myths about the laboratory origin of the coronavirus.

Rhinolophus trifoliatus / Photo: Daverbennett

In a study published in the journal Current Biology, a group of scientists from China and Australia described another coronavirus, RmYN02, recently discovered in bats. According to scientists, this virus is the closest relative of SARS-CoV-2, which has similar mutations in the viral genome, which apparently occurred as a result of natural evolution.

“Since the discovery of SARS-CoV-2, there have been several unsubstantiated assumptions that the virus is of laboratory origin. In particular, it was pointed out that the insertion of amino acids S1 and S2 is very unusual and possibly indicative of laboratory manipulations. Our article shows very clearly that these events occur naturally in the wild. This is strong evidence that SARS-CoV-2 is not a laboratory leak,”writes a microbiologist at Shandong First Medical University microbiologist Weifeng Shi.

The new coronavirus was identified by analyzing 302 samples from 227 bats collected in Yunnan province in the second half of 2019.

After analyzing the viruses found in these bat samples, the team was able to locate two nearly complete coronavirus genomes - RmYN01 and RmYN02.

RmYN01 had a very low match with SARS-CoV-2. But after studying RmYN02, the researchers, according to them, literally hit the jackpot. The genome of this coronavirus is 93.3% identical to the genome with SARS-CoV-2, and one specific gene, named 1ab, is 97.2%. To date, this is the closest match with the coronavirus that causes COVID-19, scientists emphasize.

In addition, RmYN02 contains amino acid insertions at the point where the two subunits (S1 and S2) of the spike protein meet. SARS-CoV-2 also has S1 and S2 inserts.

Scientists emphasize that despite this similarity, RmYN02 is not a direct ancestor of the virus that causes COVID-19, especially since the gene for the domain that binds all important receptors has a low coincidence with SARS-CoV-2, only 61.3 %. However, this is a very important discovery, allowing to obtain more data on the evolution of the coronavirus and to be convinced of its natural origin.

“Our study confirms that bats, especially those of the genus Rhinolophus (horseshoe bats), are important natural reservoirs for coronaviruses and currently contain the closest relatives of SARS-CoV-2, although this picture may change as the sample increases. wildlife,”scientists say.