Here’s the central tenant of the paper:
"Theories of SARS-CoV-2 origins
"It is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus. As noted above, the RBD of SARS-CoV-2 is optimized for binding to human ACE2 with an efficient solution different from those previously predicted.
Furthermore, if genetic manipulation had been performed, one of the several reverse-genetic systems available for betacoronaviruses would probably have been used. However, the genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone."
"Our analyses clearly show that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated virus."
However, a paper published in Journal of Virology, does detail a purposeful manipulation of a newly discovered bat virus (SL-CoV S) backbone involving the insertion of SARS virus sequences - to see if they could make the bat virus infectious to humans. At that stage the SL-CoV S was not infectious.
"A series of S chimeras was constructed by inserting different sequences of the SARS-CoV S into the SL-CoV S backbone."
In terms of Ace2-binding, the experiment was successful.
“ACE2-binding activity of SL-CoVs was easily acquired by the replacement of a relatively small sequence segment of the S protein from the SARS-CoV S sequence”
Far from being ‘unpredicted’, and not the way you’d go about it if you did want to enhance ACE-2 binding activity - it has been done - and - it was 'easy'.
Knowing the capability of different CoVs to recombine both in the laboratory and in nature, the possibility that SL-CoVs may gain the ability to infect human cells by acquiring S sequences competent for binding to ACE2 or other surface proteins of human cells can be readily envisaged.
The good news is that this engineering of contagious deadly diseases is all for our own good.
“The outcome of such research will also be invaluable in formulating control strategies for potential future outbreaks caused by viruses that are similar to, but different from, the SARS-CoVs responsible for the 2002-2003 outbreaks.”
How did that strategy work out btw?
The findings presented in this study serve as the first example of host switching achievable for G2b CoVs under laboratory conditions by the exchange of a relatively small sequence segment among these previously unknown CoVs.
So that paper directly refutes the Proximal Origin one which claimed to “irrefutably show” that the virus couldn’t have been engineered.
Later i checked the authors of this alternative paper - maybe they were hacks who lack credibility. Turns out there are 10 of them - guess where they come from?
Five are from Wuhan Institute of Virology, including Bat Woman, Shi Zheng-li.
Imagine that! Having your argument debunked by the very institute you’re trying to protect!
Two others involved in the SARS-like construction experiment are Aussies from the CSRIO - how they are mixed up in this i don’t know - the other three are from China. The funding of course is from the CCP.
Now at least we know a couple of things for sure:
1. Corona viruses were being 'purposely manipulated' in the Wuhan lab. They wrote a paper about it.
2. It is relatively easy to manipulate a corona virus to make it more infectious to humans by enhancing the ACE-2 binding activity in a lab.