[nudephil (OP)]

Henry wants us to debunk the following:

I am interested in the arguments to rebut a conspiracy theory that says that the furin cleavage site in the SARS-CoV-2 genetic sequence is evidence that it was made in a lab, as part of a gain of function test.

As I understand the argument, the site RRAR allows the virus much more efficiently to gain access to a human cell once it has become bound to the ACE2 receptor. When the genetic sequence is compared to other coronaviruses, some of which have a genetic similarity in the high as 90%, the furin cleavage site is not present; and you have to go (says the argument) to viruses that only share about 40% genetic similarity to find another coronavirus that has the furin cleavage site.

Such an abrupt change in such a long sequence of nucleotides, it is suggested, could not occur by natural mutation. Rather, it has been a chimeric creation by snipping part of the genetic sequence from another virus and inserting it.

I don’t know enough about the topic to come up with a viable response to this argument.

I'd be very interested to hear what the forum thinks.

[set fair]

The patern seems to be that when something suspicious is pointed out, then the researchers will "find" a corona virus that has a feature which will allay the suspicion. I haven't come to the conclusion that the virus was created in a lab but I think we are past the point where it should be labeled as a conspiracy theory.