Possible Bat Origin of Severe Acute Respiratory Syndrome Coronavirus 2

...
Although the Wuhan market was initially suspected to be the epicenter of the epidemic, the immediate source remains elusive. The close relatedness among SARS-CoV-2 strains suggested that the Wuhan outbreak probably originated from a point source with subsequent human-to-human transmission, in contrast to the polyphyletic origin of Middle East respiratory syndrome coronavirus (14). If the Wuhan market was the source, a possibility is that bats carrying the parental SARSr-BatCoVs were mixed in the market, enabling virus recombination. However, no animal samples from the market were reported to be positive. Moreover, the first identified case-patient and other early case-patients had not visited the market (15), suggesting the possibility of an alternative source.

Because the RBD is considered a hot spot for construction of recombinant CoVs for receptor and viral replication studies, the evolutionarily distinct SARS-CoV-2 RBD and the unique insertion of S1/S2 cleavage site among Sarbecovirus species have raised the suspicion of an artificial recombinant virus. However, there is currently no evidence showing that SARS-CoV-2 is an artificial recombinant, which theoretically might not carry signature sequences. Further surveillance studies in bats are needed to identify the possible source and evolutionary path of SARS-CoV-2.