1/13
I did a bit of reading on #coronavirus research today, loosening the cobwebs of what I remember from majoring in molecular biology at MIT.
Per @K_G_Andersen's paper below, the structure of SARS-CoV-2 makes it a highly improbable man-made virus.
nature.com/articles/s4159…
I did a bit of reading on #coronavirus research today, loosening the cobwebs of what I remember from majoring in molecular biology at MIT.
Per @K_G_Andersen's paper below, the structure of SARS-CoV-2 makes it a highly improbable man-made virus.
nature.com/articles/s4159…
2/13
The short summary is that the spike protein that it uses to enter human cells is similar to that of #SARS_COV_2 (the original one that resulted in the 2002-2003 SARS epidemic), but has differences that actually seem to make it LESS of a good fit.
The short summary is that the spike protein that it uses to enter human cells is similar to that of #SARS_COV_2 (the original one that resulted in the 2002-2003 SARS epidemic), but has differences that actually seem to make it LESS of a good fit.
3/13
So basically, it doesn't make sense that scientists hoping to make a bioweapon would fabricate something inferior to what already exists.
So basically, it doesn't make sense that scientists hoping to make a bioweapon would fabricate something inferior to what already exists.
4/13
Now, as it turns out, SARS-CoV-2 has proven more effective at entering human cells that one would predict from the receptor binding domain (RBG) of the spike protein.
Now, as it turns out, SARS-CoV-2 has proven more effective at entering human cells that one would predict from the receptor binding domain (RBG) of the spike protein.
5/13
That seems to be explained by the fact that there is a "cleavage site" that allows the structure of the spike protein to be altered enzymatically by naturally occurring proteases in the body. Those cleavage alterations seem to enhance human infectivity.
That seems to be explained by the fact that there is a "cleavage site" that allows the structure of the spike protein to be altered enzymatically by naturally occurring proteases in the body. Those cleavage alterations seem to enhance human infectivity.
6/13
Which makes SARS-CoV-2 highly effective at entering human cells after all, but this is much more likely to be an accident of nature than a deliberate strategy by scientists.
In other words, there are much more obvious ways scientists would go about it.
Which makes SARS-CoV-2 highly effective at entering human cells after all, but this is much more likely to be an accident of nature than a deliberate strategy by scientists.
In other words, there are much more obvious ways scientists would go about it.
7/13
That all said, research done here in the US has been investigating how altering bat coronaviruses might lead to human infectivity. In 2015, US investigators collaborating with the Wuhan lab engineered a hybrid coronavirus with that very capability.
nature.com/articles/nm.39…
That all said, research done here in the US has been investigating how altering bat coronaviruses might lead to human infectivity. In 2015, US investigators collaborating with the Wuhan lab engineered a hybrid coronavirus with that very capability.
nature.com/articles/nm.39…
8/13
And more recent work by the same US (but not Chinese) researchers also recently published on how proteolytic cleavage of a coronavirus spike protein, similar to what seems to be happening with SARS-CoV-2, could enhance human receptor binding.
jvi.asm.org/content/94/5/e…
And more recent work by the same US (but not Chinese) researchers also recently published on how proteolytic cleavage of a coronavirus spike protein, similar to what seems to be happening with SARS-CoV-2, could enhance human receptor binding.
jvi.asm.org/content/94/5/e…
9/13
Therefore, while the genetic evidence still strongly supports that SARS-CoV-2 originated "in the wild" from bats and possibly through an intermediate host like pangolins (SARS-CoV is thought to have moved from bats to humans through civets)...
Therefore, while the genetic evidence still strongly supports that SARS-CoV-2 originated "in the wild" from bats and possibly through an intermediate host like pangolins (SARS-CoV is thought to have moved from bats to humans through civets)...
10/13
...it seems just as likely that SARS-CoV-2 could have originated from a lab here in the US as in China.
Which is to say equally as NOT likely.
Once again, to be clear, the actual evidence suggests that was NOT man-made in a lab, whether in China or the US.
...it seems just as likely that SARS-CoV-2 could have originated from a lab here in the US as in China.
Which is to say equally as NOT likely.
Once again, to be clear, the actual evidence suggests that was NOT man-made in a lab, whether in China or the US.
11/13
While this kind of "reverse genetic engineering" research does play into "evil scientist" tropes that in turn lead to science-phobic conspiracy theories, it's been no secret that researchers all over the world have been studying potential human coronavirus transmission...
While this kind of "reverse genetic engineering" research does play into "evil scientist" tropes that in turn lead to science-phobic conspiracy theories, it's been no secret that researchers all over the world have been studying potential human coronavirus transmission...
12/13
...with a goal of anticipating a novel outbreak like SARS or MERS previously. We have been able to rapidly respond to #COVID19, quickly sequencing the genome and understanding how SARS-CoV-2 works based on the models generated by this previous research.
...with a goal of anticipating a novel outbreak like SARS or MERS previously. We have been able to rapidly respond to #COVID19, quickly sequencing the genome and understanding how SARS-CoV-2 works based on the models generated by this previous research.
13/13
Because that was the point of the research in the first place!
So, is the origin of COVID-19 best explained by conspiracy theories about evil scientists developing bioweapons via a #manmadevirus?
No, no, no; a thousand times no.
Because that was the point of the research in the first place!
So, is the origin of COVID-19 best explained by conspiracy theories about evil scientists developing bioweapons via a #manmadevirus?
No, no, no; a thousand times no.
@threadreaderapp unroll please
