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> "it is molecularly impossible... to result in SARS-CoV-2." That's sound ominous, but I am curious, how could it be "molecularly" impossible? My understandin

> "it is molecularly impossible... to result in SARS-CoV-2." That's sound ominous, but I am curious, how could it be "molecularly" impossible? My understanding is that as there are several other Sarbecovirus (including SARS-COV-1), what could in principle ("molecularly") forbid one of them to mutate to SARS-COV-2? Yet I am not a scientist. Thanks!

conistonwater 5y ago
There was an episode the TWiV podcast a few months ago where they discussed the biology-based evidence for why SARS-COV-2 wasn't made in a lab. I think it was this one: https://www.microbe.tv/twiv/twiv-762/ https://www.microbe.tv/twiv/twiv-762/ One nice thing about the podcast is that because they're scientists by personality they tend to focus far more on the biology of it, which I really appreciate. I listened to it at the time, but I don't remember what they said, to be perfectly honest.
- inciampati 5y ago
  As a biologist (sorry for the appeal to authority, but it matches the tone of this thread), the evidence against a natural origin appears absolutely staggering. You have a viral clade that completely descends from a single introduction event inside a major city. The virus does not undergo a period of host adaptation, but instead infects many millions over nearly a year before phenotypic changes are observed. This is simply fantastic. I know of no case where a virus jumped species without a period of adaptation to the new host. The fact that the entire clade has a root in October 2019 (and we can see this even because the first viruses sequenced differed by only one or two mutations from their common ancestor) indicates that there was not slow community spread before the initiation of the pandemic period. There is no weaker progenitor virus. Considering as well the focus of research labs within the exact city where the pandemic arose makes any argument against the laboratory origin of the virus seem extremely weak. How does a serious and non-conflicted scientist explain all of these ultra-improbable coincidences?
  - arbitrage 5y ago
    > sorry for the appeal to authority You don't need to apologize for your knowledge and experience. We are not engaged in a roman-style rhetoric class where the mandate is to build all arguments upon a set of rules we never agreed to. The wikipedia list of common logical fallacies is not a guideline to rational discourse in the 21st century.
    - ddxxdd 5y ago
      As far as I'm concerned, apologizing for the appeal to authority signalled that he was open to being criticized and challenged by layman, rather than choosing to belittle those who disagree with him without having his knowledge and experience. In short, he demonstrated that he wasn't an "elitist".
  - michaelmrose 5y ago
    An appeal to authority is only inherently invalid insofar as the authority claimed is irrelevant authority or used to paper over weaknesses in the actual argument. Forums not entirely overrun with imaginary internet doctors and cranks can probably start with the polite presumption that you are actually a biologist and proceed with reasonable discussion from there without further ado.
  - orwin 5y ago
    I agree with you for the begining, but this part: > The fact that the entire clade has a root in October 2019 (and we can see this even because the first viruses sequenced differed by only one or two mutations from their common ancestor) indicates that there was not slow community spread before the initiation of the pandemic period. There is no weaker progenitor virus. is hard for me to understand. Rural China in not rural USA. At all. I've hiked for a month in the Appalachian, another one in the Sierras, and spent two month in rural China. Rural china is as i used to imagine rural Africa. Rural china have two particularities: young, probably younger than you imagine. You have villages with a median age of 15, with no middle-aged inhabitants. And enclaved. You have villages where you have to use a jeep (that the village do not own) to get to. Is it possible, in you opinion, to have an early SRAS-Cov2 infecting a village, festing on the people for weeks or even months, then a parent coming back for his yearly vacations, getting infected, then going back to work in Wuhan? I'm not a biologist, so i don't understand how viruses works, but i _know_ rural China (and rural europe, and rural USA.)
m0llusk 5y ago
The lab was working with chimeras instead of the virus in part because they were unable to consistently culture the virus. Neither nature nor humans make a viable viruses out of chimeras.
- tim333 5y ago
  One of the chimeras (in the research the article is based on) reproduced up to 10,000x better than the virus it was based on and caused the mice to lose weight through illness. Sounds viable to me.

conistonwater 5y ago

There was an episode the TWiV podcast a few months ago where they discussed the biology-based evidence for why SARS-COV-2 wasn't made in a lab. I think it was this one: https://www.microbe.tv/twiv/twiv-762/ https://www.microbe.tv/twiv/twiv-762/ One nice thing about the podcast is that because they're scientists by personality they tend to focus far more on the biology of it, which I really appreciate. I listened to it at the time, but I don't remember what they said, to be perfectly honest.

inciampati 5y ago
As a biologist (sorry for the appeal to authority, but it matches the tone of this thread), the evidence against a natural origin appears absolutely staggering. You have a viral clade that completely descends from a single introduction event inside a major city. The virus does not undergo a period of host adaptation, but instead infects many millions over nearly a year before phenotypic changes are observed. This is simply fantastic. I know of no case where a virus jumped species without a period of adaptation to the new host. The fact that the entire clade has a root in October 2019 (and we can see this even because the first viruses sequenced differed by only one or two mutations from their common ancestor) indicates that there was not slow community spread before the initiation of the pandemic period. There is no weaker progenitor virus. Considering as well the focus of research labs within the exact city where the pandemic arose makes any argument against the laboratory origin of the virus seem extremely weak. How does a serious and non-conflicted scientist explain all of these ultra-improbable coincidences?
- arbitrage 5y ago
  > sorry for the appeal to authority You don't need to apologize for your knowledge and experience. We are not engaged in a roman-style rhetoric class where the mandate is to build all arguments upon a set of rules we never agreed to. The wikipedia list of common logical fallacies is not a guideline to rational discourse in the 21st century.
  - ddxxdd 5y ago
    As far as I'm concerned, apologizing for the appeal to authority signalled that he was open to being criticized and challenged by layman, rather than choosing to belittle those who disagree with him without having his knowledge and experience. In short, he demonstrated that he wasn't an "elitist".
- michaelmrose 5y ago
  An appeal to authority is only inherently invalid insofar as the authority claimed is irrelevant authority or used to paper over weaknesses in the actual argument. Forums not entirely overrun with imaginary internet doctors and cranks can probably start with the polite presumption that you are actually a biologist and proceed with reasonable discussion from there without further ado.
- orwin 5y ago
  I agree with you for the begining, but this part: > The fact that the entire clade has a root in October 2019 (and we can see this even because the first viruses sequenced differed by only one or two mutations from their common ancestor) indicates that there was not slow community spread before the initiation of the pandemic period. There is no weaker progenitor virus. is hard for me to understand. Rural China in not rural USA. At all. I've hiked for a month in the Appalachian, another one in the Sierras, and spent two month in rural China. Rural china is as i used to imagine rural Africa. Rural china have two particularities: young, probably younger than you imagine. You have villages with a median age of 15, with no middle-aged inhabitants. And enclaved. You have villages where you have to use a jeep (that the village do not own) to get to. Is it possible, in you opinion, to have an early SRAS-Cov2 infecting a village, festing on the people for weeks or even months, then a parent coming back for his yearly vacations, getting infected, then going back to work in Wuhan? I'm not a biologist, so i don't understand how viruses works, but i _know_ rural China (and rural europe, and rural USA.)

m0llusk 5y ago

The lab was working with chimeras instead of the virus in part because they were unable to consistently culture the virus. Neither nature nor humans make a viable viruses out of chimeras.

tim333 5y ago
One of the chimeras (in the research the article is based on) reproduced up to 10,000x better than the virus it was based on and caused the mice to lose weight through illness. Sounds viable to me.