Nor methods manipulating viruses serial passage , repeated transfer viruses one culture cells another.If virus manipulated , whether seamless method serial passage , way knowing case.Andersen colleagues assuring readers something could know.The discussion part letter begins , “ It improbable SARS-CoV-2 emerged laboratory manipulation related SARS-CoV-like coronavirus. ” But wait , ’ lead say virus clearly manipulated ? The authors ’ degree certainty seemed slip several notches came laying reasoning.The reason slippage clear technical language penetrated.The two reasons authors give supposing manipulation improbable decidedly inconclusive.First , say spike protein SARS2 binds well target , human ACE2 receptor , different way physical calculations suggest would best fit .