"Whether the new crown virus is made by American companies" has triggered a fierce discussion for several days, and the source of the discussion is an academic paper -
The researchers conducted a study of the sequence of the new crown virus, and found a surprising coincidence under the guidance of a series of clues: a sequence of 19 nucleotides in the key location of the new crown virus has been patented by the American pharmaceutical company Modena Company 6 years ago.
Screenshot of the paper
Screenshot of a patent by the American pharmaceutical company Modena Corporation
Objectively speaking, "the key sequence of the new crown virus is patented by the US pharmaceutical company" and "the new crown virus is manufactured by the company" are two completely different issues. How should we view these two issues? In order to find out the context, let's first follow the paper, review the discoveries of scholars, and then listen to the interpretation of experts.
The "Find the Difference" game features a glare of 12 nucleotides
In order to find the peculiarities of the new crown virus, many scholars have adopted a comparative approach.
The researchers compared the coronavirus to the virus that most resembles it, a bat coronavirus called RaTG13, which has a similarity of 96.3%. If you put the two sequences together, you can't see the difference in a dozen eyes. But the paper researchers did a meticulous analysis, like playing the "find the difference" game, circle the differences.
They were surprised to find that there was almost no difference between more than 3 consecutive nucleotides, which was like two deserts, maybe there was an additional sand dune here, and there were a few mounds, but there were no tall buildings.
But there was only one accident, the new crown virus sequence appeared in a key location of a 12 nucleotide insertion sequence, but not in the bat coronavirus.
Against the backdrop of similarities, the differences between the 12 nucleotides in a single place are particularly glaring, like a skyscraper in the desert. The researchers decided to look it up. At this time, they did not know what they could find.
3 coincidences that researchers consider the sequence of the new crown virus to be "very rare"
What happened to this unconventional 12 consecutive nucleotide mutations?
With this question in mind, the researchers did two aspects of analysis: functional analysis and sequence analysis.
Functional analysis is to understand what role this sequence plays in the "life course" of the new crown virus. The researchers found the corresponding protein for the translation of this sequence. It turned out that the protein it translated happened to be critical.
First of all, the location is critical: it happens to be on the most critical S protein that the new crown virus invades the human body; secondly, the function is critical, and the enzymatic resection site it encodes happens to use the flynn protease in the human body to cut itself and help the virus fuse into human cells. Many previous studies have shown that this enzyme resection site is related to the ability of the new crown virus to be infected.
Sequence analysis is to find out if the sequence has appeared elsewhere, and if so, it may indicate the source of the sequence. Through a common sequence search method, the researchers found that the complementary matching sequence of this sequence coincidentally appeared in the patent for synthetic sequences applied by Modena in 2016, and the matching length was extended from 12 to 19. At the same time, this sequence is relatively rare, existing only in the genomes of some bacteria and rarely in other species, especially in possible host animals such as bats.
In summary, this sequence leads to at least 3 coincidences:
The sequence happens to be in a key position for the new crown virus and plays a key role;
The sequence happens to appear in a patent by the American Modena Corporation (and not other companies);
The sequence also happens to be absent in most species.
The first author of the paper, Bara Ambati, a scholar at the University of Oregon in the United States, said in a recent interview with China Daily that the article was peer-reviewed and published to stimulate discussion. The team is more concerned about whether it can be experimentally proved that the recombination of the virus sequence and the artificial design sequence is feasible.
Hear what the experts have to say
With this paper, the reporter of Science and Technology Daily exclusively interviewed a molecular virology expert and asked him to answer questions.
The researchers found that the new coronavirus has 12 nucleotide-length inserts that are different from the bat coronavirus, why is it worth paying attention to?
"The nucleic acid sequences of the two viruses mentioned in the paper differ from more than 1,100 nucleotides, and they are evenly distributed among more than 30,000 nucleotides." The expert explained that, theoretically, the longer the continuous variation, the less, and the sequence alignment also proves this. That is to say, the single mutation is the most, the two variants connected together are less, the three are less connected together, and there are almost no more than three. So the 12 consecutive variants were really unexpected.
Only 19 nucleotides are the same, compared to the tens of thousands and hundreds of millions of genome volume is not insignificant?
"These 19 nucleotides are continuous, and the continuous same is highly specific." Experts explain that for every additional nucleotide in a continuous length, the odds of matching drop exponentially. For 19 consecutive nucleotides, theoretically only 4 (there are 4 nucleotides) with a probability of one in 19th of the power to find exactly the same sequence. The coincidence that a synthetic, 19-base-specific sequence appears at a key site in the viral genome and plays a very critical role is rare and difficult to understand.
Are these 19 nucleotides the key sequence of the new crown virus?
"Where it's located is critical, and so is the functionality." The expert said that this is also an important site recognized by the scientific community, and why the new crown virus is so powerful is directly related to this site.
Was the coronavirus manufactured by the company?
From the patent point of view, the sequence is designed to repair the mismatch in the tumor, because during tumor expansion, if the mismatch is aggravated, the speed and degree of its deterioration will be faster, and repairing the mismatch will help tumor treatment. As for how this sequence accurately and efficiently enters the key site of the new crown virus genome, most of the current judgments are still in the speculative stage. Whether it was purely coincidental or deliberate, it needs to be investigated and proved more deeply and extensively.
Source: Science and Technology Daily