[HN Gopher] Extracting DNA from the air - DNA evidence of human ...
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       Extracting DNA from the air - DNA evidence of human occupancy in
       indoor premises
        
       Author : punnerud
       Score  : 235 points
       Date   : 2025-03-15 18:38 UTC (3 days ago)
        
 (HTM) web link (www.nature.com)
 (TXT) w3m dump (www.nature.com)
        
       | dc396 wrote:
       | https://www.imdb.com/title/tt0119177/ was conservative. Great
       | movie though.
        
         | Mistletoe wrote:
         | I feel like this is one of those prescient movies like
         | Pleasantville and Idiocracy we should force voters to watch
         | again before voting.
        
         | bilekas wrote:
         | So glad someone mentioned that. A great movie I still enjoy
         | today!
        
       | treetalker wrote:
       | From the abstract:
       | 
       | > Detectable levels of DNA were also observed in air and dust
       | samples from ultra-clean forensic laboratories which can
       | potentially contaminate casework samples.
       | 
       | Great news for criminal defense attorneys.
        
         | thfuran wrote:
         | The defense attorneys of criminal criminal forensics lab
         | technicians at least.
        
           | Hupriene wrote:
           | Dexter Morgan wins again.
        
           | looofooo0 wrote:
           | Phantom of Heilbronn strikes again:
           | https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
        
         | moontear wrote:
         | How would that argument go? As far as I understand it, the DNA
         | of the occupants of said lab may be found. That would mean that
         | the criminal samples may also contain DNA of the lab
         | occupants/scientists. Isn't that the case currently as well and
         | those DNA parts would be omitted?
        
           | archerx wrote:
           | What if the murderer works in the lab?
        
             | a_bonobo wrote:
             | The Phantom of Heilbronn!
             | 
             | https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
        
               | archerx wrote:
               | That was interesting story, the ending in hindsight seems
               | obvious. Thank you for sharing.
        
           | greenpresident wrote:
           | That would ideal, yet we still got things like this:
           | 
           | https://en.wikipedia.org/wiki/Phantom_of_Heilbronn
           | 
           | Woman at a cotton swab factory was identified after being
           | considered a serial killer.
        
           | yzydserd wrote:
           | It's possibly not the GP's point, but in general the more DNA
           | that is available the better from a defense perspective. Many
           | wrongful convictions involve a lack of physical evidence.
           | Recent advances like "touch dna" and "m-vac" have led to new
           | DNA evidence used in actual innocence decisions. Too often, a
           | jury convicts a likely suspect on weak circumstantial
           | evidence. Just as with Touch DNA, Air DNA will create new
           | problems with avoiding contamination.
           | 
           | The path toward Air DNA has been known for years [0].
           | Wouldn't be surprised to learn crime scene investigators have
           | been sampling and storing air in high profile cases ready for
           | the tech to catch up.
           | 
           | [0] https://www.science.org/content/article/dna-pulled-thin-
           | air-...
        
         | mrtksn wrote:
         | It cuts both ways, there was this high profile case of the son
         | of a very rich and powerful family brutally murdering his
         | working class girlfriend in his family mansion with some family
         | present, motives still unknown.
         | 
         | In the autopsy they discovered sperm from a 3rd person on her
         | body, tried to claim that it was an infidelity case(you get
         | different sentece depending on your motives and circumstances)
         | but later it was revealed that this was just a contamination
         | during the autopsy.
         | 
         | So, the more forensic options the better but likely longer and
         | more expensive trials. All lawyers win.
        
           | paulluuk wrote:
           | > just a contamination during the autopsy.
           | 
           | How does sperm end up on her body during the autopsy? Are we
           | talking necrophilia or are there multiple murdered bodies
           | laying next to each other and the tools are re-used or
           | something?
        
             | mrtksn wrote:
             | IRRC The official explanation is that there were a few
             | autopsies going on at the same time in that facility and it
             | came from the body next to hers. The public opinion was
             | that they bribed the technician to contaminate her body.
             | 
             | The whole case is a huge mess with attempts of cover ups,
             | months long manhunts and all kinds of conspiracy theories.
             | The killer was sentenced to 24 years of prison but unalived
             | himself in prison and there're still conspiracy theories
             | saying that he actually escaped to China because he was
             | studying Chinese in prison prior that. This happened more
             | than 10 years ago and last year they opened his grave to
             | check the remains and again it was confirmed that that's
             | him. Yet, this is still not enough to end the public
             | discussion and conspiracy theories.
             | 
             | Anyway, if anyone is curious this is the case in question:
             | https://en.wikipedia.org/wiki/Murder_of_Munevver_Karabulut
             | 
             | Unfortunately, the juicy literature around that is mostly
             | in Turkish.
        
               | bozhark wrote:
               | You can say he killed himself it's not kitkots
        
               | genewitch wrote:
               | Tiktots?
        
               | nkrisc wrote:
               | > unalived himself
               | 
               | In English the phrase is "killed himself".
        
               | mrtksn wrote:
               | Feel free to use your choice of synonym when you are
               | writing something.
        
               | SketchySeaBeast wrote:
               | Normally I'm more than happy to roll with someone's
               | choice of words - if you want to use "literally" to
               | describe things that are not literal, please, fill your
               | skibidi or whatever, but I'm hostile towards it when it's
               | an attempt to appease a corporation's filters. I get it,
               | you gotta use it where you gotta use it, but I hate the
               | indicators that our language is being filtered everywhere
               | by certain social media's moderation rules.
               | 
               | That's not language changing because of fresh eyes, it's
               | because of tired eyes looking towards the bottom dollar.
        
               | mrtksn wrote:
               | It's not about filters, I like using unalive in the
               | context of suicide when I have no sympathy to the person
               | who dies. It's such a nice dehumanizing word.
        
               | SketchySeaBeast wrote:
               | But it's entered the vernacular because of the filters.
        
               | mrtksn wrote:
               | That's true, some day in the future somebody will make 5
               | seconds long, long format documentary about the
               | fascinating origins of the word :)
               | 
               | It has a passive aggressive character, I like that word a
               | lot.
        
               | SketchySeaBeast wrote:
               | I get the opposite out of it. Using the negative prefix
               | weakens the word, emphasizing what it is not instead of
               | what it is, when act like suicide is not just the state
               | of being not alive. The phrasing isn't committed enough
               | to be oxymoronic and it ends up feeling impersonal and
               | indirect.
               | 
               | But maybe I'm just an old man yelling at a cloud.
        
               | kube-system wrote:
               | Pick any sentence and trace the words back to their
               | origin and you'll find some sort of story about where it
               | was borrowed from. That's just how language works. It
               | isn't anything new -- we're all just older than we've
               | ever been. Every generation coins new terms.
        
               | SketchySeaBeast wrote:
               | I'm not against language growth, but the reason this is
               | happening is upsetting to me.
        
               | ZacNorth wrote:
               | If you're taking the time to write one or more posts
               | about this, you are implicitly against language growth,
               | you've just found a justification for being against it
               | that you find acceptable to your worldview.
        
               | SketchySeaBeast wrote:
               | Yes, there are occasions where I would take exception to
               | language evolution. If we entered a pattern of 1984-era
               | newspeak I'd take exception there as well. I think it is
               | usually the product of a poorly considered stance for one
               | to be an absolutist about the vast majority things.
        
               | kube-system wrote:
               | Euphemism is already common, particularly when discussing
               | sensitive topics like the cycle of life, bodily
               | functions, etc. You are probably okay with many existing
               | euphemisms because they are familiar. This really isn't a
               | social media thing, newspaper obituaries also use
               | euphemisms for death. e.g. "passed away", "departed",
               | "eternal rest", etc.
        
               | SketchySeaBeast wrote:
               | Yes, because that euphemistic language is there to
               | lighten the blow. "unalive" is an attempt to bypass a
               | social media filter and speaks to the shift in how and
               | why words enter our lexicon.
        
               | kube-system wrote:
               | Are you against profanity filters? What's the difference?
        
               | SketchySeaBeast wrote:
               | Well, because "suicide" isn't profane. It might be
               | considered a pseudo-profanity, but people don't stop
               | saying swearing because of profanity filters. This is an
               | instance where the filter is feeding back into the
               | zeitgeist.
        
               | nkrisc wrote:
               | It sounds kinder and gentler, to me, more like a word
               | you'd use in polite company to avoid speaking crassly
               | about someone respected.
        
               | mrtksn wrote:
               | Suicide is a statement, it is the last act of somebody
               | against the society. It is something serious that puts
               | the burden on the shoulders of the remaining. It has
               | long, deep history attached to it.
               | 
               | Unalive on the other hand is a simplistic word that has
               | neither of those, it is originally derived as an attempt
               | to bypass automatic filter. IMHO using it for someone
               | without the practical need to bypass censorship takes
               | away the heft of their act. Makes it insignificant.
        
               | itishappy wrote:
               | HN doesn't filter "suicide" though. This is organic
               | language. Free-range, grass-fed, and GMO-free.
        
               | SketchySeaBeast wrote:
               | Yeah, my argument is we shouldn't use "unalive" when we
               | don't have to.
        
               | adolph wrote:
               | you just did tho
               | 
               | (I am currently reading and infected by Hofstadter's
               | "Surfaces and Essences: Analogy as the Fuel and Fire of
               | Thinking" which I think would side with using unalive,
               | which might also construe a set larger than that of
               | "dead.")
        
               | JoshTriplett wrote:
               | https://en.wikipedia.org/wiki/Use%E2%80%93mention_distinc
               | tio...
        
               | SketchySeaBeast wrote:
               | I quoted it for specificity. I suppose I could have said
               | "the word formerly known as suicide" but that is probably
               | a phrasing that anyone young enough to unironically use
               | the word formerly known as suicide wouldn't understand.
        
               | inetknght wrote:
               | > _I 'm hostile towards it when it's an attempt to
               | appease a corporation's filters_
               | 
               | Maybe you should be hostile towards the corporations that
               | create those filters instead.
        
               | kossae wrote:
               | Why not both?
        
               | SketchySeaBeast wrote:
               | Yes. I am more upset by the one responsible for the
               | filtering than the effect it's having on the zeitgeist.
        
               | nkrisc wrote:
               | I only mentioned it because it took me a few moments to
               | figure out what you had actually written since I assumed
               | it was a typo or mistranslation. It distracts from what
               | you've written.
        
               | unwind wrote:
               | TIL that the kids actually use it [1], and it's in
               | dictionaries [2] etc so arguably it's actually English.
               | 
               | [1]: https://medium.com/new-writers-welcome/unalive-the-
               | birth-of-...
               | 
               | [2]: https://www.dictionary.com/browse/unalive
               | 
               | Edit: typo.
        
               | weberer wrote:
               | They only say it to avoid word filters on certain
               | algorithm-driven sites. Your comment won't be
               | automatically flagged, demoted, or shadow banned here for
               | using naughty words that corporate advertisers don't
               | like.
        
               | skyyler wrote:
               | Surely you can understand that when certain behaviours or
               | phrases become fashionable, they can become detached from
               | the culture that generated them.
        
               | accrual wrote:
               | I'm in agreement, but one thought that crossed my mind is
               | how the population in China self-censors and I wonder if
               | this is kind of like that. Rather than tailor the
               | terminology to different environments, the person just
               | chooses the "safe" term all the time.
        
               | skyyler wrote:
               | When was the last time you were in China? I'm curious
               | about this self-censoring you're talking about. Did you
               | observe it personally?
        
               | kossae wrote:
               | There are 10s if not 100s of articles on it, and even a
               | paper written about it:
               | https://as.nyu.edu/content/dam/nyu-
               | as/politics/documents/The.... One does not have to be in
               | China or observe it personally to know of its existence.
        
               | skyyler wrote:
               | Okay, so from the one you linked:
               | 
               | >Respondents who are the most highly educated, have the
               | highest number of daily posts on social media, and spend
               | the most time on social media, appear to self censor
               | criticisms of the government on social media more than
               | they self censor praise of the government on social
               | media. Other respondents do not appear to self-censor
               | criticism of the government on social media. However, my
               | findings are severely limited by my small sample size.
               | 
               | I was actually asking for accounts of firsthand
               | experience, not ideological slop.
        
               | kube-system wrote:
               | That is the origin of the phrase, but it has since
               | entered colloquial vernacular... as pretty much all terms
               | used on social media do.
        
               | catigula wrote:
               | I haven't seen that, I find it strange.
        
               | kube-system wrote:
               | You're wouldn't be the first adult to be unfamiliar with
               | slang. Language spreads socially.
        
               | BurningFrog wrote:
               | The word filters must adapt pretty soon. So we'll get new
               | terms.
        
               | boromisp wrote:
               | The next gen is semantic and sentiment filters, the age
               | of wordlists is over.
        
               | kortex wrote:
               | And early Europeans avoided saying the name of the
               | terrifying land mammal out of taboo / fear it would
               | summon it, and instead referred to it as either "the
               | brown one" or "wild animal" (exact etymology is unclear
               | which it was), giving us the word "bear", to the point
               | where the "arktos" based word has been lost. Often times
               | euphemisms stick.
               | 
               | https://en.wikipedia.org/wiki/Bear#Etymology
        
           | moralestapia wrote:
           | Interesting. Link or something?
        
             | mrtksn wrote:
             | I provided some more details and a link here:
             | https://news.ycombinator.com/item?id=43396911
        
       | steve_adams_86 wrote:
       | At work we do this with DNA floating around in the ocean (have to
       | track down all those nasty invasive crabs) but I wouldn't have
       | guessed we could do this with the air around us as well. That's
       | so cool.
       | 
       | Maybe we should spin up an air-based version for the office to
       | keep track of who's in coming to work the most
        
         | faangguyindia wrote:
         | More like who is sick a lot (sneezing and distributing dna on
         | multiple surfaces in the blast radius)
        
         | MostlyStable wrote:
         | Yeah, eDNA is exactly what I thought of when I saw this.
        
         | DecentShoes wrote:
         | Jeff Bezos is probably already throwing millions of dollars at
         | this in case it'll help him punish people for having a toilet
         | break.
        
           | Lanolderen wrote:
           | Fart detector
        
         | SpicyUme wrote:
         | Do you think this would become doable by private citizens in
         | the near future for a reasonable amount of money? I've been
         | curious about how far upstream the sculpins are in our local
         | streams. I've seen some in pretty small streams but looking for
         | them typically involves standing still in very cold water for
         | long enough to see them move.
        
       | a_bonobo wrote:
       | This is a slightly older paper, note that air environmental DNA
       | now has progressed a lot, especially for species mapping.
       | 
       | Here's a cool recent paper showing you can extract DNA of local
       | species from spider webs, by sequencing DNA stuck to spider webs
       | from next to a zoo
       | https://www.sciencedirect.com/science/article/pii/S258900422...
        
       | h1fra wrote:
       | I have always wondered why DNA is an accepted evidence. It's so
       | easy to contaminate a crime scene or bring someone else hair,
       | skin cells, etc by mistake.
        
         | rwmj wrote:
         | In theory, you could do a "perfect crime" by going to a seedy
         | part of town, picking up a dropped cigarette butt, and leaving
         | it at the crime scene, framing someone else.
         | 
         | In reality, criminals are angry, frightened, in a rush, high or
         | stupid, and they make the most elementary mistakes, so DNA and
         | fingerprints work just fine almost all the time. In like 99% of
         | cases there's not much doubt about who did it, the main thing
         | is to have a watertight case against them when they deny it.
        
           | serf wrote:
           | >so DNA and fingerprints work just fine almost all the time.
           | 
           | except for all of those innocent folks that have had their
           | lives ruined by that 'almost all the time' caveat, it's
           | great!
           | 
           | here's a report[0] that says something like 80% + of criminal
           | forensic work has major mistakes within it.
           | 
           | [0]:
           | https://www.criminallegalnews.org/news/2024/may/15/report-
           | fi...
        
             | rwmj wrote:
             | Quoting from that:
             | 
             |  _> At 100% of the 130 examinations analyzed, seized drug
             | analysis was the examination with the highest percentage of
             | Type 2 errors. It was followed by pediatric physical abuse
             | (83% of cases had forensic errors with 22% having Type 2
             | errors out of 60 cases analyzed), fire debris not including
             | chemical analysis (78% of cases /38% Type 2 in 45 cases),
             | bitemark comparison (77% of cases/73% Type 2 in 44),
             | pediatric sexual abuse (72% of cases/34% Type 2 in 64),
             | serology (68% of cases/26% Type 2 in 204), shoe/foot
             | impressions (66% of cases/41% Type 2 in 32), DNA (64% of
             | cases/14% Type 2 in 64), hair comparison (59% of cases/20%
             | Type 2 in 143), and blood spatter (58% of cases/27% Type 2
             | in 33)._
             | 
             | Also this sample comes from cases where people were
             | exonerated, which could cluster around poor quality police
             | work in general. And is US-based where policing is all
             | kinds of messed up.
        
           | abecedarius wrote:
           | When we're talking about quality of evidence, saying "in
           | reality" is skipping to your conclusion. Are smart careful
           | people rare among known criminals? Well, yes. What would you
           | expect to see? https://www.econlib.org/archives/2015/02/the_w
           | ittgenstei.htm...
        
           | adolph wrote:
           | > going to a seedy part of town, picking up a dropped
           | cigarette butt, and leaving it at the crime scene
           | 
           | I've sometimes conjectured collecting hair from barbershops
           | and making a dusting bag that steadily fluffs out hairs to
           | dirty up a crime scene. Maybe get some saliva from grocery
           | store sample spoons.
        
           | inetknght wrote:
           | > _you could do a "perfect crime" by going to a seedy part of
           | town, picking up a dropped cigarette butt, and leaving it at
           | the crime scene, framing someone else_
           | 
           | Framing someone else is not a perfect crime. A perfect crime
           | finds no criminal, accused or convicted.
        
             | UncleEntity wrote:
             | Creating reasonable doubt as a backup plan in case your
             | perfect caper isn't as perfect as you believe is just good
             | practice.
             | 
             | Rule 43(a) in the criminal procedures handbook IIRC.
        
         | Ajay-p wrote:
         | Because people believe it, and courts have accepted as fact
         | that DNA evidence is infallible. Certainly there have been
         | cases where DNA has been successfully challenged, but those are
         | very rare. In the overwhelming number of cases where DNA
         | evidence is present, it is a self-fulfilling prophecy for
         | juries and judges.
         | 
         | If there is DNA evidence that is almost a guilty verdict. It
         | should be more closely scrutinized but not everyone is rich
         | enough to afford a real defense.
        
         | antiquark wrote:
         | Reminds me of the case of David Butler.
         | 
         | "Mr Butler has a rare skin condition, which means he sheds
         | flakes of skin, leaving behind much larger traces of DNA than
         | the average person. He worked as a taxi driver, and so it was
         | possible for his DNA to be transferred from his taxi via money
         | or another person, onto the murder victim."
         | 
         | https://www.bbc.com/news/science-environment-19412819
        
       | rgrieselhuber wrote:
       | So, DNA shedding basically?
        
       | water-data-dude wrote:
       | Well, that's going to make it harder to hide from the hunter-
       | killer bots
        
       | the__alchemist wrote:
       | This article... keeps repeating phrases about criminals,
       | authorities, safe-houses, solving crimes. Feels off. I was
       | expecting this to focus on the lab techniques, feasibility,
       | technical details. It jumps straight from forensic application
       | details to results without the in-between. I think the in-between
       | is the interesting part.
       | 
       | It's as if they took the token sentence that goes in an abstract
       | about potential applications, and turned it into the meat of the
       | article.
       | 
       | It sounds like they are using standard extraction kits, them
       | analyzing with RT-PCR.
        
       | 6d6b73 wrote:
       | I wouldn't be surprised that some some agencies
       | *cough*Mosad*cough* are gathering DNA of leaders of all
       | countries, and analyzing them, and potentially building
       | bioweapons to target them. It looks like all you need to do is to
       | get the HEPA filter from the room where the target was .
        
         | tehjoker wrote:
         | This sounds very expensive, of uncertain efficacy, and if you
         | use an engineered organism, it will likely be detected if you
         | use modified DNA.
         | 
         | I accept an agency like Mosad or the CIA would attempt it
         | though. CIA tried so many crazy schemes to try to kill or
         | embarrass Castro and failed every time. Mosad loves balls to
         | the walls evil schemes too, like the pagers. It would be one of
         | those situations where they leave a stupid trace and everyone
         | knows it's them and they are untouchable so they don't care and
         | even enjoy the attention.
        
       | Simon_O_Rourke wrote:
       | If you know my mother in law, you don't need a DNA tester to know
       | she's been in the restroom.
        
       | michaelcampbell wrote:
       | Anyone remember the movie Gattaca?
        
       | jp57 wrote:
       | Makes me wonder if dogs can smell your DNA.
        
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