On April 2, the Suzhou Center for Disease Control and Prevention introduced at a press conference on the epidemic that the city discovered the evolutionary branch of Omicron BA.1.1, and no highly homologous sequences of the new coronavirus genome were found in multiple databases.

　　Has there been a new mutation of Omicron that has never been seen before in China?

How did this variation arise?

Has the new coronavirus evolved again?

Can the epidemic still be prevented?

　　Although the Suzhou Center for Disease Control and Prevention emphasized that it will take some time to analyze and compare before releasing further information.

However, this new mutation still attracted widespread attention and speculation, and it was on the hot search.

With the above questions, a reporter from Science and Technology Daily interviewed a virology expert on the national data platform.

　　It's too early to judge by sequencing similarity alone

　　"'No highly homologous sequences have been found', such a statement is not scientific enough." The expert said, first of all, the meaning of the report should be "highly similar sequences". In biological evolution research, "homology" only can be described as "yes" or "no"; secondly, the meaning of "height" is imprecise, both 99.9% and 99% may be considered "height", but the number of sequences caused by the difference between these two similarities The change is as high as more than 200 nucleotides; finally, the change of the genome sequence does not mean that the virus's transmissibility, infectivity, pathogenicity, etc. will inevitably change, and it cannot be judged only by the number of sequence differences whether there is a new epidemic variant. It should be further analyzed whether the sequence variation has caused the change of the corresponding amino acid, which protein this variation occurs on, and if it is an important protein, whether it is in the key region.

Only when these are studied clearly, can we know the possible consequences of the new strain.

Therefore, when disclosing the "new branch" of Omicron, the mutation site must be announced at the same time.

　　Whether it is a "new branch" is currently uncertain

　　The Suzhou Center for Disease Control and Prevention mentioned in the bulletin that the discovery of the BA.1.1 evolutionary branch of the Omicron variant strain means that it has mutated to a certain extent?

　　"For the new branch of the new coronavirus, there are different definitions internationally." The expert told a reporter from Science and Technology Daily that some definitions are more extensive and some are more detailed.

Academia has different classification methods and established different standards.

　　A reporter from Science and Technology Daily checked the literature and learned that after analyzing more than 35,000 pieces of new coronavirus genome information, some scholars proposed a dynamic naming method "PANGO" in July 2020, and other scholars have also proposed different classification methods.

　　Take the more widely used "PANGO" method as an example, which stipulates that a new subclade must have sufficient phylogenetic evidence to prove that the descendant lineage has changed from ancestral lineage to descendant lineage during the epidemic process of populations in a different geographical area. evolutionary process, that is, the subclades must have substantial forward propagation.

At present, this variant sequence has only been detected from one infected person, and it is difficult to confirm that it has substantial forward transmission, so it may not necessarily be defined as a new branch.

　　'New branch' unsurprisingly likely to 'fly on its own'

　　"This round of local epidemics has been going on for more than a month. According to the mutation rate of the new coronavirus, it is normal to have two or so mutations." The expert said, but it does not mean that the new branch of the new coronavirus will become severe as soon as it appears. Only the more "adapted" viruses are likely to survive, and even if they survive, they may not develop into mainstream strains.

　　"If you go back to the delta strain, you will find that it has many branches AY.1, AY.2...AY.133, but only a few finally become mainstream." The expert explained that a large number of branches are in the process of epidemic. In "self-destruction".

Therefore, even if a new branch emerges, there is no need to panic, and the branch may not eventually form a mainstream, and rarely develop into a more infectious and pathogenic strain.

　　The important thing is to collect a large number of samples from people who are currently positive for COVID-19 for viral genome sequencing, closely monitor the variation through bioinformatics methods, detect mainstream virus strains in a timely manner, and develop effective vaccines, antiviral drugs and detection reagents to prevent and control the epidemic. .

　　Our reporter Zhang Jiaxing