From “The Science Suggests a Wuhan Lab Leak: The Covid-19 pathogen has a genetic footprint that has never been observed in a natural coronavirus,” by The Wall Street Journal‘s Steven Quay and Richard Muller:

“Proponents of zoonotic origin must explain why the novel coronavirus, when it mutated or recombined, happened to pick its least favorite combination, the double CGG. Why did it replicate the choice the lab’s gain-of-function researchers would have made?

“Yes, it could have happened randomly, through mutations. But do you believe that? At the minimum, this fact — that the coronavirus, with all its random possibilities, took the rare and unnatural combination used by human researchers — implies that the leading theory for the origin of the coronavirus must be laboratory escape.”