Bat coronaviruses related to SARS-CoV-2 and infectious for human cells

The closest Laotian relatives bind human receptors efficiently — and carry no furin cleavage site

what the source states

"We found that the receptor-binding domains of these viruses differ from that of SARS-CoV-2 by only one or two residues at the interface with ACE2, bind more efficiently to the hACE2 protein than that of the SARS-CoV-2 strain isolated in Wuhan from early human cases, and mediate hACE2-dependent entry and replication in human cells … None of these bat viruses contains a furin cleavage site in the spike protein." On genome identity: "RaTG13 and BANAL-52 bat coronaviruses exhibit high nucleotide identity with SARS-CoV-2 throughout the length of the genome (96.8% for BANAL-52 and 96.1% for RaTG13)."

what we infer

A single paper carrying evidence in both directions, which is why it is recorded whole. It demonstrates that efficient human-receptor binding evolves in wild bat sarbecoviruses with no laboratory involved, which weakens one engineering argument — and it confirms that none of these natural relatives has the cleavage site, which is the observation the other engineering argument rests on.

limitations

• A survey of one geographic region; absence of a feature among sampled viruses is weak evidence about its natural distribution.