Lawrence Sellin "far more likely scenario is that native receptor binding domain within a bat coronavirus “backbone” was artificially replaced

5-15-20    COVID-19’s receptor binding domain, which allows the attachment of the virus to a human cell, is structurally closer in its amino acid sequence to that of pangolins (scaly anteaters) than to bat RaTG13.

COVID-19 -

N S N N L D S K V G G N Y N Y L Y R L F R K S N L K P F E R D I S T E I Y Q A G S T P C

N G V E G F N C Y F P L Q S Y G F Q P T N G V G Y Q P Y

Pangolin -

N S N N L D S K V G G N Y N Y L Y R L F R K S N L K P F E R D I S T E I Y Q A G S T P C

N G V E G F N C Y F P L Q S Y G F H P T N G V G Y Q P Y 

RaTG13 -

N S K H I D A K E G G N F N Y L Y R L F R K A N L K P F E R D I S T E I Y Q A G S K P C

N G Q T G L N C Y Y P L Y R Y G F Y P T D G V G H Q P Y        

  As you can see, the pangolin sequence differs from COVID-19 by only one amino acid (10th letter from end), while RaTG13 differs in seventeen positions.

Within the receptor-binding domain there are fourteen specific amino acids that were previously shown to be critical for coronaviruses to bind to the angiotensin-converting enzyme-2 receptor that initiates the COVID-19 infection in humans.

At least two pangolin species match those critical COVID-19 amino acids in thirteen out of fourteen positions, whereas RaTG13 matches only seven out of fourteen and other bat coronaviruses do so to an even lesser extent.

  Chinese scientists suggest that the pangolin receptor binding domain was “donated” to COVID-19, presumably through some type of recombinant event occurring between a bat coronavirus and a pangolin coronavirus inside a pangolin host.  Their naturally-occurring explanation for the presence of a pangolin-like receptor binding domain is highly speculative and no evidence exists to support such a contention.

  A far more likely scenario is that the native receptor binding domain within a bat coronavirus “backbone” was artificially replaced with one from a pangolin strain.

After that came the insertion of the furin polybasic cleavage site, found in COVID-19 and none of the close bat coronaviruses relatives yet identified and a distinctive feature is widely known for its ability to enhance pathogenicity and transmissibility in coronaviruses.

  There is additional information now being discussed on virology blogs indicating that COVID-19 is not naturally-occurring because its differential ratio of synonymous to non-synonymous substitution is vastly different compared to that which occurs in nature among bat populations as well as natural factors that would select against the presence of a furin polybasic cleavage site.   

-Ret. US Army Col. L. Sellin   https://www.wionews.com/opinions-blogs/explained-scientific-indications-that-show-covid-19-is-man-made-298868

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