Air is full of DNA

(nature.com)

105 points | by howrude 2 days ago

7 comments

  • azalemeth 2 hours ago

    I do often wonder about stories like this in the context of forensic science – my (incomplete!) understanding a lot of the time suspect DNA samples are taken from small areas and amplified significantly with high-cycle count PCR. I'd worry that any jury presented with a statistical argument about a fragment of somebody's DNA being very unlikely ("1 in 100 million") to be different to the sample found at the scene would not be aware of all of the potential systematic reasons why the actual true probability may be much, much higher.

    • Terr_ 2 hours ago

      Probability seems to be one of those things humans habitually mess-up at.

      "The chances of this person's unique DNA showing up at the scene are a zillion to one!"

      "What does that really mean when the sample also contains unique DNA for a hundred other people? Did all of them commit the crime as a group?"

    • butvacuum 2 days ago

      buried the lede, imho: we have enough DNA profiles to match their sampling up with.

      I'm always stunned when reminded that a full genome sequencing has gone from Human Genome Project's extreme cost and (edit: glacial) speed to using seqencing as the easy button.

      I hear we've also got machines that'll seqence, fit on a bench, and cost high five/low six figures. They've got issues to work out still though- iirc something about damaged sections causing issues.

      • cmrx64 2 days ago

        four figures these days. fits in your hand. nanopore is a revolution. https://nanoporetech.com/products/sequence/minion

        there’s youtubers that have videos about doing this in a home wetlab. very achievable. some amateur soil biologists using this to try and sample microdiversity as the planet… humanifies.

      • smolder 3 hours ago

        Paleontology has been really helped by the ease of sequencing, to the point where many evolutionary arguments are moot. Humans are apes, birds are dinosaurs. Some people still dispute it, but not with evidence on their side.

      • globular-toast 3 hours ago

        Should be noted, though, the cheaper/quicker techniques do still come with compromises compared to the "gold standard" technique used for the Human Genome Project.

      • nelox 1 hour ago

        What a wonderful title, a breath of fresh air.

      • dkobia 1 hour ago

        This always blows my mind. We are currently breathing in the DNA of the trees, animals, and people around us—and we’re leaving ours behind for them, too. We’re all one big genetic soup.

        • gus_massa 10 minutes ago

          The immune system destroy all the DNA in unexpected places in case it's a https://en.wikipedia.org/wiki/Viroid or something. Better safe than sorry.

          One of the important steps in mRNA vaccines was to surround the mRNA with a lipid to ensure it can survive long enough to enter a cell. Naked mRNA would not have worked.

          • red75prime 24 minutes ago

            "Soup" is a good word. Pieces of DNA resulting from destruction by nucleases and other enzymes.

            • SideburnsOfDoom 52 minutes ago

              > This always blows my mind. We are currently breathing in the DNA of the trees,

              At this time of year, believe me, I am aware of the inhaled tree DNA setting off my pollen allergies.

            • seydor 2 hours ago

              Let's wait for smartphones with nanopores

              • madaxe_again 4 hours ago

                I was chatting with a biologist friend a while back, and one tidbit he dropped in was that any sample of air from anywhere on earth will likely contain the dna of organisms unknown to science, so abundant the tree of life is.

                • rcxdude 11 minutes ago

                  Yeah, there's just so many microorganisms (and some evolve so quickly) it would basically be impossible to really enumerate the species.

                  • scotty79 1 hour ago

                    I firmly believe that there are thousands of times more species of viruses in circulation that influence human health, almost always in minor fashion, than we currently know. Any random, sub-clinical symptom is in my belief highly likely to be caused by one of such viruses.

                  • dang 4 hours ago

                    [stub for offtopicness]