3 ms·

Double check the query coverage percentage on your searches.

• yellowapple 5y ago
  Yep, you're right (and edited above to reflect that). After accounting for that, and after realizing that BLAST only returns the first 100 results, I searched on the "nt" database (where the article found "only" SARS-CoV-2 results) while excluding SARS-CoV-2 (taxid:2697049), "synthetic construct" (taxid:32630), and "other sequences" (taxid:28384). This¹ produced not just a lot of hits, but a lot of exact (i.e. 19/19) hits (mostly various microbes) - further suggesting that even the exact sequence in question ain't unique. I also ran a search on "nt" strictly on SARS-CoV (i.e. the original SARS virus)², and while no single result completely matches the query, there are a lot of results that could be concatenated/combined to produce the query - and while I'm (again) no geneticist, it doesn't seem to me like some sort of impossibility for that concatenation to happen through mutations in the wild. ¹: https://blast.ncbi.nlm.nih.gov/Blast.cgi?CMD=Get&RID=Y3WR4BPX013 https://blast.ncbi.nlm.nih.gov/Blast.cgi?CMD=Get&RID=Y3WR4BP... ²: https://blast.ncbi.nlm.nih.gov/Blast.cgi?CMD=Get&RID=Y3YCNK2C013 https://blast.ncbi.nlm.nih.gov/Blast.cgi?CMD=Get&RID=Y3YCNK2...
  • dnautics 5y ago
    Unless there is a transposable element between them, Just so concatenations like that are two independent splicing events so you roughly expect a quadratic likelihood reduction (square the rarity)
    • yellowapple 5y ago
      Which would still be a lot more likely than "random chance" (as the article puts it - i.e. each of those 19 nucleotides being randomly selected), right?
      • dnautics 5y ago
        I'm not going to defend any of the statistics in the article.