[The Epoch Times] Later, Li and Shi jointly conducted a gain-of-function study published in the Journal of Virology in September 2015 on the MERS virus and a bat virus (strain HKU4) in 2015. Since MERS virus can enter human cells but HKU4 can not, they introduced 2 single mutations in the HKU4 spike protein and found that the new mutant S protein can enable HKU4 to enter human cells. If they mutated 2 sites in MERS spike, the resulting MERS pseudovirus (experimental virus) cannot enter human cells anymore.Furthermore, Shi's group joined an international group to generate a chimeric virus with the bat virus SHC014 they harvested in Yunnan. Since they know SHC014 is unlikely to bind to human ACE2, they "synthesized the SHC014 spike in the context of the replication competent, mouse-adapted SARS-CoV backbone". So, that is a lab-engineered virus with SARS-CoV Mouse adapted backbone (MA15) but with SHC014 spike.
To their surprise, the chimeric virus (SHC014-MA15) can use SHC014 spike to bind to human ACE2 receptor and enter human cells. SHC014-MA15 can also cause disease in mice and cause death as well. Existing vaccines to SARS cannot protect animals from SHC014-MA15 infection. Therefore, these chimeric virus studies can lead to the generation of more pathogenic, more deadly CoV strains in mammalian models.
Due to the U.S. government-mandated pause on the gain-of-function (GOF) studies, this international research did not proceed further at that time. However, there is no evidence that Shi's group in China stopped any further study on the track of introducing GOF mutations on the CoV. And it is clear that Shi's group already mastered the reverse-engineering technology that is sufficient to introduce mutation in current SARS-CoV or SARS-Like CoV to create mutant infectious coronavirus.
Interestingly, Shi's group published on bioRxiv on Jan. 23, 2020 that a new bat coronavirus that they detected in Yunnan, named BatCov RaTG13, shares 96.2 percent overall genome sequence identity with 2019-nCoV. However, this virus was never mentioned or published in their research before.
Long, semi-technical article regarding work done in 2007 - 2019. Scroll down to the section labelled "Track Record of Wuhan Institute of Virology on Engineering ’Gain-of-Function’ Bat SARS-Like CoV"