Thread by @vipintukur

Is this the first direct evidence for a lab leak origin of COVID19?
A new research has again fuelled the debate on the origin of SARS2. Was SARS2 originated as an infectious clone assembled in vitro? 1/

But, why is it important to know exactly the origin of SARS2?

To prevent future pandemics, it is critical that we understand whether SARS2 spilled over directly from animals to people, or indirectly in a laboratory accident. 2/

The genome of SARS2 contains a peculiar pattern of unique restriction endonuclease recognition sites allowing efficient dis- and re-assembly of the viral genome characteristic of synthetic viruses. 3/

Here, the researchers report the likelihood of observing such a pattern in coronaviruses with no history of bioengineering. They find that SARS2 is an anomaly, more likely a product of synthetic genome assembly than natural evolution. 4/

The restriction map of SARS2 is consistent with many previously reported synthetic coronavirus genomes, meets all the criteria required for an efficient reverse genetic system….5/

It differs from closest relatives by a significantly higher rate of synonymous mutations in these synthetic-looking recognitions sites, and has a synthetic fingerprint unlikely to have evolved from its close relatives. 6/

The researchers conclude a high likelihood that SARS2 may have originated as an infectious clone assembled in vitro. 7/

biorxiv.org/content/10.110…

@BallouxFrancois : “These findings are not 'final and dispositive', but they can't be ignored either. To me, this is by far the strongest piece of evidence to date against a simple scenario of strict zoonotic origin for SARS-CoV-2.”

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https://twitter.com/washburnealex/status/1583145276151189504