Air is full of DNA (nature.com)
115 points by howrude 3 days ago
azalemeth 4 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_ 3 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?"
chiph 9 minutes ago
Depends on how they're using it. To find an unknown person and prove they were at a scene - yeah you'll have the 100 person's worth of DNA to sort through and then match against a (presently) incomplete DNA database. But if you already have a suspect and need to place them at the scene, if their DNA is one of the 100 then they have shown that.
ch4s3 7 minutes ago
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.
robertlagrant 36 minutes ago
Ex-Nanopore employee here. One interesting thing we heard about internally was that OceanX[0] has one of our GridION[1] devices (slightly larger, and built-in compute) that they were using to track whales in the ocean by sequencing DNA found in seawater. Really cool.
dubi_steinkek a day ago
Do you have links to these youtubers? Sounds interesting
samplatt 4 hours ago
smolder 4 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.
pfdietz 2 hours ago
> birds are dinosaurs
Not that I doubt that, but how does DNA help, when we have no DNA samples from dinosaurs?
Terr_ 3 hours ago
> Some people still dispute it
I particularly like this Futurama clip on the subject. https://m.youtube.com/watch?v=VzGtk7Ip4NU
globular-toast 4 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 2 hours ago
What a wonderful title, a breath of fresh air.
nasretdinov 2 hours ago
A breath of fresh _DNA_
dkobia 2 hours 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.
red75prime an hour ago
"Soup" is a good word. Pieces of DNA resulting from destruction by nucleases and other enzymes.
SideburnsOfDoom 2 hours 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.
gus_massa an hour 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.
seydor 4 hours ago
Let's wait for smartphones with nanopores
madaxe_again 5 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 an hour ago
Yeah, there's just so many microorganisms (and some evolve so quickly) it would basically be impossible to really enumerate the species.
scotty79 2 hours 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 6 hours ago
[stub for offtopicness]