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  • Covid 19 myths have spread just about as quickly as the disease itself.

  • But one myth in particular just won't go away.

  • That SARS cov to the virus that causes Covid 19 isn't naturally occurring and was actually man made.

  • In fact, one substantial survey found that almost 30% of Americans believe that this virus came from a lab.

  • But scientists believe that they can confidently say that the virus wasn't created by humans, and the myth going around is nothing more than that.

  • A myth.

  • So how do they know with such certainty?

  • The key is in the virus's genetic code?

  • This is the genomic sequence for SARS Cov two.

  • It was decoded in January 2020 just weeks after the world started to learn of this novel coronavirus.

  • Each of those letters is a genetic building blocks known as a nucleotide, and when built up, they form an organism's genetic code, which we can use to understand them.

  • Each organism has a different code and a varying amount of nucleotides.

  • A human has about three billion of them, whereas a virus such as SARS COV two has about 30,000.

  • Your genetic sequence can give information about your hair, eye color, sex and lineage.

  • And just like your jeans give clues about who and where you come from.

  • Scientists can use a virus genome sequence to help explain where that virus originated as well.

  • An ancestry test for viruses, if you will.

  • We hummed in on the parts of the virus that we thought were unique, and it might play a role in the evolution of the virus, but also in the pathogenesis of it.

  • And a couple of things stood out pretty quickly when we started to compare with the other Corona viruses that have come before.

  • That's Robert Garry, a professor of microbiology and immunology at Tulane University.

  • Along with his colleagues, he used the virus sequence to try and understand where SARS cov two came from.

  • They first looked at the virus's backbone.

  • That's the whole genomic structure unique to each virus.

  • Like a viral template simplified the backbone for SARS cov two, and it's 30,000 nucleotide looks a little bit like this.

  • Each section is responsible for a part of the virus.

  • For example, this one is responsible for the spike proteins you may have seen lining the virus shell, so it may not come as a surprise that to engineer a virus in a lab you would need to start with a backbone.

  • But to manufacture from scratch the backbone of a virus that can also cause disease is almost impossible.

  • I mean, people just don't know enough about what makes the virus pathogenic to be able to symbol that.

  • How do you pick amongst all the possibilities to get to that last little bit?

  • That's going to turn it into this world wide pathogen?

  • Which sequences do you think about to put in there?

  • Simply?

  • There is just not enough knowledge about how to make a new virus that would also cause significant devastation.

  • Like SARS.

  • COV two has so creating a new deadly backbone is pretty much impossible.

  • But there is another way.

  • The novel coronavirus could have been created in a lab and that would be using an existing virus backbone or genetic sequence as a starting point with a recycled backbone.

  • Two main methods could have been used to create the new virus.

  • They could have either quickly mutated it or added and deleted parts of the existing virus.

  • But additions and deletions and a virus leave a trace that can be pointed out pretty quickly, a little bit like removing a red brick from a wall and replacing it with a black brick.

  • This is exactly what Macek Bony, an associate professor at Penn State, looked for.

  • You might see an insertion that looks unusual, and you look out in nature and you see that no other viruses have genetic insertions like that.

  • We did not see any genetic insertions that not also identified in nature, so there's no evidence suggesting that it was man made or laboratory created somehow.

  • So what if they went with the other option and mutated an existing virus?

  • This is known as serial passage and acts in a similar way to selective breeding.

  • Scientists are able to mimic evolution to a degree by forcing the virus to mutate over and over again into a potentially different form.

  • This can be used to weaken a virus, which is how some vaccines have been made, or to strengthen a virus, say, by making it more transmissible.

  • But for this to work, the existing virus would have to show significant genetic similarity to the new virus.

  • In fact, they would have to be almost identical because this process only speeds up viral evolution and has a limit.

  • It's not possible to direct mutations into a completely different form.

  • Yet Gary and his team found that the backbone for SARS cov two was strictly unique, differing significantly from other Corona viruses.

  • For example, SARS cov the first Stars has only about a 79% genetic sequence match to SARS cov two.

  • So it's ruled out the best candidate is R 80 g 13, a bat coronavirus with a 96% gene sequence.

  • Similarity 96% sounds pretty close, but in genetic terms, that's actually pretty long ways away.

  • To put it in perspective, humans and chimpanzees share 99% of the same genome, and you may have noticed there's still a large difference between the two for SARS cov two and R 80 g 13.

  • That 4% is the difference of about 800 nucleotides, or about 50 years of natural evolution.

  • 800 is too big a barrier.

  • You had something that was 99.5% or 99.7% similar.

  • Maybe only 20 or 30 nucleotides, you might get away with it.

  • You might be able to manufacture that doing the lab, but it just wouldn't be possible with current knowledge and existing viruses.

  • There's also another part of the gene sequence that helped Gary and his colleagues learn about the natural origins of sars-cov-2, in particular this set of nucleotides in the gene sequence.

  • You might remember those from earlier they're responsible for the virus spike proteins.

  • The pointy claw like arms lining the outside of the virus that give it its distinctive appearance and coronavirus is their name.

  • Specific viruses, including coronavirus, is use these arms to enter and take over host cells.

  • But this piece of the spike protein help tell the researchers that this virus originated in nature.

  • This set of nucleotides relates to the receptor binding domain, or RBD.

  • That's the part that latches onto the receptors on targeted cells as viruses can only survive when inside other cells.

  • This is a vital section that you would have to focus on if you were to make a virus in a lab, Gary and his team found.

  • The RBD has evolved specifically to bind to the human cell a C to a receptor usually used to help regulate blood pressure, but it's the way it's so successfully binds to the A C two receptor that is crucial.

  • You see, when a scientist tests what aspects would make a virus more potent, they run models through computer simulations.

  • But when researchers put this sequence through those simulations, they found that sars-cov-2 RBD shouldn't be successful at all.

  • And what actually caused poor efficiency and transmission, which we know is not the case by working in the lab, working with computer, trying to figure it out.

  • I mean, they just would not have come up with this particular way to have this virus buying this receptor a very important part of the whole replication process.

  • In other words, if your goal was to make a virus to infect humans, you wouldn't have chosen this one.

  • Basically, what nature has been has come up with a solution for binding that is better than any computer and ultimately better than what any scientists could come up with.

  • So we know why.

  • Scientists confidently say Sars-cov-2 wasn't made in a lab.

  • But that's not the end of the story.

  • It's also been rumored that Sars-cov-2 was a known virus that was accidentally leaked from a lab now we can't say for certain this isn't the case, but it's highly unlikely.

  • For one, this virus wasn't sequenced before January 2020.

  • And if it was, the world would know because the Wuhan Institute of Virology was specifically looking for something like this.

  • In order to protect the world from any outbreaks, they would have come up with the SARS coronavirus.

  • That was 76% similar to the original stars.

  • One, I mean, they would have published that as fast as they could.

  • That would have been, at least in the scientific world, very big news.

  • But it's also just statistically highly unlikely.

  • So just that in nature, there literally beings of people that are having millions of encounters with these animals.

  • And, you know, we're talking about a handful.

  • A few dozen made in the whole world of scientists that go out and trap that.

  • So just on the odds of the things, that's just a minuscule chance that it was just one scientists that accidentally better themselves.

  • And that's very sophisticated laboratory setting.

  • So Sars-cov-2, whose origin is no longer a mystery but where and how it jumped in nature.

  • Well, that's a question many are still trying to answer.

  • Mhm.

Covid 19 myths have spread just about as quickly as the disease itself.

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How We Know The Coronavirus Wasn’t Made In A Lab

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    林宜悉 posted on 2021/03/25
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