It is an undeniable fact that the new coronavirus is still changing in our unknowable direction, in the face of the new coronavirus over the SARS virus, the most worrying thing for researchers is still coming. On March 3, the National Science Review, sponsored by the Chinese Academy of Sciences, published “On the Origin and Continuity of SARS-CoV-2” (On the origin and continuing evolution) on-of-SARS-CoV-2).
An evolutionary analysis of the largest 103 new coronavirus whole genome molecules to date found that the strain had 149 mutation points, 101 of which could be classified as L and S subtypes. The S type is a relatively old version, while the L sub type is more aggressive and more contagious. In terms of percentage, the L subtype is more common, at 70%, and the S subtype is 30%.
In this regard, many netizens also expressed concern: “I suspect that the virus has an IQ.”
New coronaviruses may be divided into two types, not recent mutations
It is worth noting that today afternoon, according to the interface news report, industry media BioArt team analyzed the relevant research team research, said: there are media called “new coronavirus has mutated” system misreading, correct understanding should be: the new coronavirus can be divided into L, S two types according to different mutation sites of the genome, But these two mutants may have existed early in the virus outbreak, not recently.
So, what the hell is going on? I’m afraid it’s going back to the paper itself.
S subtype is the “ancestor” of the L subtype, has not been recombined?
Lei Feng learned that the study selected 103 virus genome sequences and found that 149 mutation points had occurred in the virus strain, including 43 syiyi mutations and 83 misnomermutations (nonsy mutations), while 70% of virus sequences have 7 identical mutations, plus 1 identical mutation (L84S), which affects the functionality of the virus’s 6 proteins.
Analysis of the derived mutation spectrum of 103 new coronavirus strains, orange as non-synonymous mutation and green as synonymous mutation (pictured from the paper)
The study classified 70% of these mutated viruses as the L subtype of SARS-CoV-2 (L derived from the mispronounced mutation L84S), while S84L was referred to as s subtype.
According to the authors, according to the evolution of the new coronavirus, there may be a big difference in the propagation ability and s-type transmission and the severity of the disease.
To further study the relationship between L-type and S-strains, the researchers reconstructed their evolutionary tree based on the whole genome sequence of 103 SARS-CoV-2 viruses.
Evolutionary tree of 103 new coronavirus strains (source from the paper)
The difference between the two subtypes is further confirmed.
In the SARS-CoV family, the sequence of other older viruses is S84L. Therefore, the study suggests that the L subtype, which is currently prevalent, evolved from the S subtype, which is actually the “ancestor” of the L subtype.
It is worth noting that the study analysis suggests that the two subtypes did not have a circular recombination of nature, and the SNP analysis further confirmed this lineage classification, with 72 virus sequences being T28144, or code L, and 29 virus sequences being C28144, or code S. The L type is A T base (for leucine, Leu) and the S type is C base (for serine, Ser).
By comparing it with other coronaviruses, the authors found that the S subtype of new coronavirus and the bat-derived coronavirus were closer to the evolutionary tree, leading to the conclusion that the S subtype is relatively old.
The L subtype is more common in the early stages of the outbreak in Wuhan, while the frequency of the L subtype has decreased since early January 2020. The authors argue that human intervention may put greater selective pressure on the L subtype, without which the L subtype may be more aggressive and spread more quickly. On the other hand, because of the relatively weak selection pressure, older and less aggressive S-types may increase in relative frequency.
A natural inference is that the relatively old new S-type coronavirus should produce more strains because it has more time to spread among people. However, genomic data show that L-type is 70% and S-type is 30%, and that each L-type strain carries a relatively large number of new mutations than type S. Why is the relatively young l-type new coronavirus producing more strains? The authors speculate that the L-type virus is more powerful to spread, or replicates more quickly in the human body, which may mean it is also more viable.
Differences in time and spatial distribution between the two neo-coronavirus subtypes (source from the paper)
The authors then compared changes in the proportion of S-type and L-type around January 7, and found that the l-type decreased in the proportion of the virus strain and the proportion of S-type increased. The authors also make their own assumptions about this somewhat unusual change , as China has taken strong vaccination measures , and patients with the L virus may be more likely to show symptoms and therefore more susceptible to human intervention , resulting in more negative selection pressure sons and fewer infections .
In addition, the 103 samples showed that most patients were infected with only one of the L or S subtypes. But one of the U.S. patients with a recent history of travel in Wuhan isolated a strain of the virus that suggests it may have been infected with both the L-type and S-type new coronaviruses. However, the authors say it is not possible to rule out a new variant.
Overall, the study systematically describes the evolution of viruses in population transmission through genomic analysis of 103 SARS-CoV-2. At the same time, the authors note that these findings mean that there is an urgent need for further comprehensive research in the context of genomic data, epidemiological data, and a 2019 coronavirus patient’s clinical symptoms chart record.
Don’t panic, the virus mutation conforms to the normal epidemiological law
Still, the news has raised everyone’s minds. If the virus mutates, will it make the outbreak worse? For a time, the discussion about the new coronavirus mutation on Weibo was on the rise.
BioArt offers a more convincing statement:
On the one hand, the need for scientific research personnel to bring more authoritative, more professional interpretation (it needs to be mentioned, we all know that scientific research is more of a “hypothesis – verification hypothesis – negative hypothesis – and then put forward a new hypothesis” process, so we should also give researchers more tolerance, because the original scientific research is constantly improved and developed);
On the other hand, in this era when everyone is the media, how can adhere to the bottom line, do not blindly interpret scientific conclusions, do not spread the content of non-responsibility, but also every individual in the communication chain node to think.
In addition, the authors stress that the new coronavirus is not a recent mutation and differentiation into L and S types, but that these two mutations may have existed in the early stages of the virus outbreak, and that current isolation and medical measures have reduced the frequency of the l-type, which may be more harmful. This result shows that the current strategies and measures for epidemic prevention and treatment are completely correct and productive.
Of course, their results are based on very small sample sizes and are largely based on molecular evolution. More comprehensive information on virus evolution also requires more experts to use more samples combined with clinical data to verify it.
Perhaps we should be more patient now, after all, the medical and medical staff who are fighting on the front lines want to end this war a little earlier than we do.