The day is growing ever closer when Washington may have to add to its agenda with Beijing a nettlesome item it has long sought to avoid: the increasingly likely fact that China let the SARS2 virus escape from the Wuhan lab where it was concocted, setting off the Covid-19 pandemic that killed some 7 million people globally and wrought untold economic havoc.
New documents may explain why no one has been able to find the SARS2 virus (aka SARS-CoV-2) infesting a colony of bats, from which it might have jumped to people. The reason would be that the virus has never existed in the natural world. Documents obtained by U.S. Right to Know, a health advocacy group, provide a recipe for assembling SARS-type viruses from six synthetic pieces of DNA designed to be a consensus sequence—the genetically most infectious form—of viruses related to SARS1, the bat virus that caused the minor epidemic of 2002. The probative weight of the recipe is that prior independent evidence already pointed to SARS2 having just such a six-section structure.
The documents unearthed by U.S. Right to Know, and analyzed by its reporter Emily Kopp, include drafts and planning materials for the already-known DEFUSE proposal, an application to DARPA, a Pentagon research agency, for a $14 million grant to enhance SARS-like bat viruses.
The new recipe is in striking accord with a theoretical paper published in 2022 that predicted the SARS2 virus had been generated in exactly this way. Three researchers—Valentin Bruttel, Alex Washburne, and Antonius VanDongen—noted that the virus could be cut into six sections if treated with a pair of agents known as restriction enzymes and so had probably been synthesized and assembled in this way.
Restriction enzymes, made naturally by bacteria as a defense against viruses, are an invaluable tool for biologists because they cut DNA at specific points known as recognition sites. These sites occur randomly across the genome, so a natural virus treated with a restriction enzyme will be cut into pieces of different sizes. However, researchers who want to synthesize a virus from scratch in order to manipulate its parts more effectively will often rearrange the recognition sites so that they are evenly spaced. This allows short chunks of DNA, all of roughly equal length, to be synthesized chemically and then strung together in a complete viral genome. Bottom line: if your virus has evenly spaced recognition sites, it’s a pretty good bet that it was made in a laboratory.
Bruttel and his colleagues guessed that a commonly used pair of restriction enzymes, known as BsaI and BsmBI, might have been used to assemble the SARS2 virus’s genome. When they examined the structure of SARS2, they found that the recognition sites used by these enzymes were indeed evenly spaced across the genome, marking it into six sections. “Our findings strongly suggest a synthetic origin of SARS-CoV2,” they wrote.
Their paper did not receive the attention it deserved, in part because of the difficulty of ruling out a natural explanation for the even spacing. The small group of virologists who adamantly oppose the lab-leak hypothesis attacked the paper as “confected nonsense” (Edward Holmes) and “kindergarten molecular biology” (Kristian Andersen).
The recipe in the new DEFUSE drafts, however, closely resembles the one posited in the Bruttel article in saying that new viruses would be constructed from six sections of DNA synthesized in a lab. The documents even include a form for ordering the BsmBI restriction enzyme.
“The DEFUSE draft documents show that, exactly as we had postulated, they planned to use 6 segments to assemble synthetic viruses, to use unique endonuclease sites that do not disturb the coding sequence, and TO BUY BsmBI !!!” Bruttel wrote in a post on X….