[HN Gopher] A Response to "The Origins of SARS-CoV-2: A Critical...
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       A Response to "The Origins of SARS-CoV-2: A Critical Review"
        
       Author : dapearce
       Score  : 35 points
       Date   : 2021-10-12 20:45 UTC (2 hours ago)
        
 (HTM) web link (ayjchan.medium.com)
 (TXT) w3m dump (ayjchan.medium.com)
        
       | Causality1 wrote:
       | I would enjoy a deeper dive on the reasons why the covid genome
       | doesn't tell us whether it's zoonotic or lab-created. In my
       | ignorance I figured that genetic modification left signatures in
       | the genome that could be recognized.
        
         | sampo wrote:
         | One way to increase the virulence of a virus in lab, is to let
         | it infect cells in cell culture, and replicate for a large
         | number of generations. This is sort of natural evolution,
         | guided in a lab, and doesn't involve genetic modification.
        
           | angelzen wrote:
           | We'll never know for sure. Which is too bad, because the plan
           | of "Let's comb remote caves for hundreds of dangerous
           | pathogens, bring them to a lab in the middle of a 10M
           | metropolis, then perform gain-of-function research on them"
           | is as nutty as it sounds.
        
         | Obi_Juan_Kenobi wrote:
         | The only 'signature' one could expect is from flanking
         | sequences. Some viruses, transposons, and bacteria leave such
         | sequence, but it is not universal. And we're talking about
         | organisms here, whole genomes of many mega/giga-bases vs.
         | viruses of mere kilobases. Even knowing what to look for, it
         | can be quite difficult:
         | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4940375/
         | 
         | In a lab setting, a simple restriction digest and recombination
         | can yield a modification with no signature, or else you can
         | generate SNPs with PCR. And you would want to, as viral genomes
         | are so small, often with overlapping ORFs, that you don't have
         | much room to leave a bunch of junk around.
         | 
         | There is no signature. What we can do is look at sequence
         | similarity and decide how probable or improbable a given
         | sequence combination is from the viral genome sampling
         | available. It's a lot of handwavy Bayesian statistics, based on
         | incomplete sampling.
        
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       (page generated 2021-10-12 23:01 UTC)