ValerieCurren (@ValerieCurren)

Apparently this tweet has Already Been Deleted 😡 Charles Small @C_Small_ · 17h Just over six years ago, I found something unusual in the data for the closest match to the pandemic virus SARS-CoV-2. Soon after the pandemic began, the Wuhan Institute of Virology published RaTG13, having previously called it BtCoV/4991 in a short sequence published pre-pandemic. Strangely, 6/33 published reads of RaTG13 were labeled “7896”, the name of a different betacoronavirus kept in the Wuhan lab. Why would the lab, known for splicing different viruses together, name part of one virus after another? Naturally, I wondered if RaTG13 was actually a composite virus of the original BtCoV/4991 and 7896. I shared the finding in the Drastic group chat and we investigated it, with @franciscodeasis then publicly alerting @Ayjchan to the dates in the amplicon sequences, who then mapped out the lab’s work progress with RaTG13 before the pandemic. The Wuhan lab has since released a virus they claimed to be the original 7896. The parts of RaTG13 labeled 7896 are a close match to the published 7896 virus, but not quite it. So what did they publish? Another virus? Another composite? Splicing viruses together and then testing how well the composite viruses bind to human cells was exactly what the lab did (See this summary from 2021: https:// zenodo.org/records/217049 10 ). But the 7896 parts of RaTG13 may not be from a different virus spliced together. If we take them at face value, the lab appears to have been using 7896 as part of the sequencing process, a sort of reference point to amplify and see what they were looking at in RaTG13. According to the lab, they started using new sequencing equipment in 2018 so would not have had to do that any more, but these were dated June 2017. The six RaTG13 7896 sequences cover the area around the RdRp and are labeled 1, 2 and 4. The area which would have been 3 is where the already published short BtCoV/4991 RdRp sequence should be, so it looks like they started with that then expanded coverage using parts of what they already had from 7896. This tells us about their pre-pandemic workstream. As some of the published RdRp sequences of the group of viruses including 7896 are identical, the Wuhan lab must have had longer sequences from them to be able to tell them apart. It tells us that the lab was working on some of the most similar viruses to the pandemic one as a group before the pandemic, using parts of their research into one to inform research into another. And why were they doing this work in the run up to the pandemic? The latest date in the RaTG13 amplicon sequences was only 11 weeks before a project testing human ACE2 receptor binding of two novel bat SARS-related coronaviruses was due to begin in January 2019. Was the work in preparation for that? https://x.com/C_Small_/status/2084282592379941272