Your paper states: “The acquisition of an FCS in the spike protein of SARS-CoV-2 that is absent in its closest relatives that circulate in Rhinolophus bats has been the subject of much controversy. Lack of knowledge about the frequency and mechanism by which insertion mutations occur in RNA viruses has led some commentators to cite its presence as evidence of human manipulation.” But characterizing the argument for possible human manipulation as arising from a lack of knowledge about the frequency or mechanism of insertion mutations is a strawman. The main reason the SARS-CoV-2 FCS has raised concerns about a possible laboratory origin is that, prior to the emergence of SARS-CoV-2, scientists explicitly proposed experiments to introduce such sites into the spike proteins of SARS-related coronaviruses. Your paper ends with the conclusion that “the emergence of coronaviruses with FCS at the S1/S2 boundary is largely a function of host environment-dependent selective pressures, and is not limited by the frequency with which they are generated through natural mutational processes.” Given that the discussion specifically mentions the SARS-CoV-2 FCS in the context of possible human manipulation, your paper should be careful to distinguish between two different questions: (1) whether coronaviruses are capable of acquiring an FCS through natural mutational processes (which your experiments address), and (2) whether the SARS-CoV-2 FCS actually arose through such a process (which your experiments do not address). Thus, as written, your paper mischaracterizes why possible human manipulation has been considered and, in doing so, misrepresents the relevance of these results to the question of how the SARS-CoV-2 FCS originated. This raises the question: why did you omit this highly relevant context from the discussion section of your paper?