evidence: Geography aside, the nature of the experiments undertaken by the W.I.V. and its partners has raised concerns. In 2015, Shi was a co-author on a groundbreaking study, in Nature, with Ralph Baric, a coronavirus expert at the University of North Carolina. Through the use of pioneering genetic technology, Baric examined which viral structures could give a coronavirus the ability to infect humans. The work involved synthesizing what is known as a chimeric virus, named for the mythical beast with its parts taken from various animals; in this case, a modified clone of SARS was combined with a spike protein taken from one of the bat coronaviruses that Shi had discovered in Yunnan. [...] The DARPA proposal stated that scientists would introduce furin cleavage sites into lab-created versions of SARS-related coronaviruses, recovered from bats in Yunnan. They planned to fully sequence and generate clones of three to five novel bat viruses each year. Then they would test the altered viruses in human respiratory cells, and, potentially, in humanized mice. "This describes work that is, like, ‘Let’s go out and discover new viruses,’ " Andersen said, "and do things like furin cleavage sites. So, yes, that’s why this is relevant to the wider conversation."