The lab-leak theory: inside the fight to uncover Covid-19’s origins
&gt; Wade devoted a full section to the “furin cleavage site,” a distinctive segment of SARS-CoV-2’s genetic code that makes the virus more infectious by allowing it to efficiently enter human cells.<p>&gt; Within the scientific community, one thing leapt off the page. Wade quoted one of the world’s most famous microbiologists, Dr. David Baltimore, saying that he believed the furin cleavage site “was the smoking gun for the origin of the virus.” Baltimore, a Nobel Laureate and pioneer in molecular biology, was about as far from Steve Bannon and the conspiracy theorists as it was possible to get. His judgment, that the furin cleavage site raised the prospect of gene manipulation, had to be taken seriously.<p>Furin cleavage sites have evolved and are present in multiple coronaviruses:<p>- HCoV-OC43 (infects humans)<p>- HCoV-HKU1 (infects humans)<p>- MHV-A59<p>- ChRCoV-HKU24<p>- BtCoV-ENT<p>- BtNeCoV-PML-PHE1<p>- BtCoV-HKU4<p>- BtCoV-HKU5<p>- MERS-CoV<p>- BtHpCoV-Zhejiang2013<p>- SARS-CoV-2<p>Phylogenetic analysis suggests that it has evolved independently at least 6 times that we know of.<p><a href="https:&#x2F;&#x2F;www.sciencedirect.com&#x2F;science&#x2F;article&#x2F;pii&#x2F;S187350612" rel="nofollow">https:&#x2F;&#x2F;www.sciencedirect.com&#x2F;science&#x2F;article&#x2F;pii&#x2F;S187350612</a>...<p>After that article was published a team in Thailand found furin cleavage sites in sarbecoviruses closely related to SARS-CoV-2 called RacCS203 (91.5% similarity to SARS-CoV-2) and RmYN02 (93.3% similarity to SARS-CoV-2)<p><a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC7873279&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC7873279&#x2F;</a><p>Furin cleavage sites are common, nature understands how to utilize that trick very well, and continuously has re-discovered it.