An international team — which included Michael Worobey, an evolutionary biologist at the University of Arizona; Kristian Andersen, a virologist at the Scripps Research Institute in California; and Edward Holmes, a biologist at the University of Sydney — started mining the new genetic data last week.
One sample in particular caught their attention. It had been taken from a cart linked to a specific stall at the Huanan market that Dr. Holmes had visited in 2014, scientists involved in the analysis said. That stall, Dr. Holmes found, contained caged raccoon dogs on top of a separate cage holding birds, exactly the sort of environment conducive to the transmission of new viruses.
The swab taken from a cart there in early 2020, the research team found, contained genetic material from the virus and a raccoon dog.
“We were able to figure out relatively quickly that at least in one of these samples, there was a lot of raccoon dog nucleic acid, along with virus nucleic acid,” said Stephen Goldstein, a virologist at the University of Utah who worked on the new analysis. (Nucleic acids are the chemical building blocks that carry genetic information.)
After the international team stumbled upon the new data, they reached out to the Chinese researchers who had uploaded the files with an offer to collaborate, hewing to rules of the online repository, scientists involved with the new analysis said. After that, the sequences disappeared from GISAID.
It is not clear who removed them or why they were taken down.
Dr. Débarre said the research team was seeking more data, including some from market samples that were never made public. “What’s important is there’s still more data,” she said.
Scientists involved with the analysis said that some of the samples had also contained genetic material from other animals and from humans. Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada, who worked on the analysis, said that the human genetic material was to be expected given that people were shopping and working there and that human Covid cases had been linked to the market.