Strategies to Prevent DNA Contamination

Discussion in 'privacy general' started by mirimir, Mar 3, 2015.

  1. mirimir

    mirimir Registered Member

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    From my guide on "Paying Anonymously with Cash and Bitcoins":
    Also, a little searching gives me this:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC55129/

    If it's safe enough to inhale, perhaps it could be incorporated into a skin creme.

    Also see https://www.sigmaaldrich.com/conten...gma/General_Information/2/biofiles_issue2.pdf at pp. 8-9 for commercial bovine pancreatic DNAse.

    And please, keep this technical, and avoid political ranting.
     
  2. noone_particular

    noone_particular Registered Member

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    Interesting subject. Unless you want to do like Leslie Neilson did in Airplane, wear a full body condom, keeping your DNA confined to your person is impossible. IMO, the only viable alternative is contamination. I don't know what is involved in separating human DNA from that belonging to all other organisms. It would make sense that the difficulty would grow in proportion to the number and types of DNA in the sample. By extension, the best "contaminant" would be something that's loaded with lots of DNA from all kinds of sources. I can think of one item right off that meets that criteria, live compost. Everything in compost was or is alive and contains DNA, including potentially hundreds of different kinds of plants, insects, small creatures, and an uncountable quantity of bacteria, fungus, and other micro-organisms, many of which consume other matter, including DNA.

    The simplest ways of contaminating the DNA we leave behind would be distasteful to many people. DNA collected from clean clothes, clean hands, and the surfaces they contact is comparatively clean. By comparison, a pair of outdoor work gloves will be carrying DNA from many sources. One could get a new pair of thin cloth gloves, then make a trip to a local animal shelter and give all of the occupants a little attention. That would have the fringe benefit of making their lives a bit more pleasant and making them more adoptable.

    It seems to me that paper currency would have to be carrying DNA from many people, especially small bills that have seen some wear and tear.

    What might be helpful is a list of chemicals, cleaners, etc that are known to break down DNA.
     
  3. deBoetie

    deBoetie Registered Member

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    The witty thing of course would be to clone the DNA of various champions of privacy such as Clapper and Alexander and spread that around. Actually, that's a horrific idea.

    My view is that the big problems with DNA collection and storage are:- a) unless it applies to everyone (including foreigners! everyone in the world!), it's not good justice b) LCN amplification and similar techniques alter the balance of reliability and increase risk of contamination and c) juries and the judicial system are - how to put this politely - utterly terrible at statistics and Bayesian inference, making miscarriages of justice far more likely.

    The UK operated illegally for some years after a damning unanimous ECHR judgement because they kept innocent peoples' DNA.

    From a privacy perspective, I think the "normal" surveillance is far easier for law enforcement, unless we're talking serious crime in which case DNA evidence is normally a valuable tool (bothways) - providing of course the safeguards above are respected.
     
  4. mirimir

    mirimir Registered Member

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    For the purposes of this question, let's assume that adversaries are collecting DNA. Whoever they are ;)

    Only contamination with human DNA is useful. One could cut up a mixture of DNA from many people with restriction endonucleases. That way, no individual sequence would be distinguishable.

    For cleaning, a DNase spray is the only way to go. It's fast, and will keep working until it dries out.
     
  5. Veeshush

    Veeshush Registered Member

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    So https://en.wikipedia.org/wiki/Forensic_science

    I think it'd be impossible to fully do anything too meaningful out in the real world to avoid it unless you're a walking clean room bubble or live the rest of your life off the grid, as a full hermit. That said, because there's no automated system to collect all samples out in the world, at every location, and because we don't live in a perfect world- I doubt you'd have to do much to fight it. It is concerning, don't get me wrong, but I think the dangers are more fear mongering (especially with media depictions) than anything considering all the high level targets it's been used against throughout history and failed on both ends of the spectrum (or even proven innocence in some cases).

    edit

    In before someone claims they're an HBO show writer and wants to know opinions on trash bags and fishing boats. :argh:
     
  6. noone_particular

    noone_particular Registered Member

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    I don't see why that would be the case. As far as I know, there's no simple, inexpensive way to separate human cells, DNA, etc from that of another species. The more species or types of DNA present, the greater the chance that they wouldn't get the human DNA completely isolated, which would ruin the results.
     
  7. mirimir

    mirimir Registered Member

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    Actually, I do know something about this stuff. Although it's been quite a while since I was seriously into it. The issue here isn't separation per se. It's isolation and amplification of particular sequences from the sample, using the polymerase chain reaction (PCR).
    http://en.wikipedia.org/wiki/Polymerase_chain_reaction
     
  8. driekus

    driekus Registered Member

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    Ok, have a pretty good background in molecular biology so can chime in here.
    In short if they want to get you they will.

    The major issue that you are going to have with the RNase is that for RNase to work it needs to be able to get into the cells or split the cells open. Given the partial effectiveness it is likely you will have some DNA leftover that is detectable. PCR is very effective at detecting small quantities of DNA.

    As for the animal contamination, most modern PCR tools have methods for separating contaminant non-target species DNA, whether it be animal or more likely bacterial.

    Contamination with other human DNA would potentially work although they probably would gain enough information from it for probable cause to get a full DNA sample.
     
  9. mirimir

    mirimir Registered Member

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    OK, SDS plus restriction endonucleases or DNase, then. I know this from experience. Spin down 100 microliters or so of HeLa cells (or whatever) and lyse with SDS, and you get snot. Add a little DNase, and in seconds, no more snot :)

    Also, the issue that I'm focusing on is DNA contamination. Your DNA sequence may be on file, along with all of your Internet traffic, but neither hurts you as long as they can't link some sample of interest to you.
     
  10. noone_particular

    noone_particular Registered Member

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    Semantics. Isolating your DNA means separating it from all of the other DNA in the sample. Sure, it can be done, but it all costs. The more types and sources of DNA in the sample, the greater the cost and work it takes to isolate yours. It also increases the potential for errors.
    If you're being investigated for an actual crime, giving them DNA gets hard to avoid. That said, collecting your DNA just to include you in a national database is not probable cause. They resort to tactics like trying to get your DNA from the seat you were in when they don't have probable cause.
     
  11. Veeshush

    Veeshush Registered Member

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    I just want to say all the same that the discussion and learning of forensics is a benefit to mankind. So while most of this might not be applicable in our own life, ever, it's still very much warranted to learn and understand. It's a good needed topic.
     
  12. noone_particular

    noone_particular Registered Member

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    Agreed. I don't claim to be particularly knowledgeable about forensics, but I've seen enough to conclude that it's accuracy is misrepresented badly. Even if one assumes that the science is accurate and unbiased, the same can not be said for the individual performing the tests or interpreting the results. IMO, forensics is little better than evidence for sale, sold to the highest bidder. The state almost always has the most money.
     
  13. mirimir

    mirimir Registered Member

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    It's not semantics. Using PCR is rather like googling a sample of restriction-cut DNA. All sequences that begin with the primer (OK, that are complementary to the primer) get amplified by many orders of magnitude. So in the end, those amplified sequences comprise 99.99999% of the processed sample. There is no separation involved.
     
  14. Veeshush

    Veeshush Registered Member

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    I remember reading this in the news a bit ago.

    http://www.nbcnews.com/business/consumer/ny-ag-takes-aim-popular-herbal-supplements-n299161

    Using as a less than perfect example, my point would be that the tests are less than perfect and the samples are less than perfect. (in my example there's probably a bit of both going on- false positive readings and valid ones). But yeah, I'm grasping at straws here for tame examples, but I feel if you want to really further it then there's going to have to be real world scenarios and a ton of examples in criminal investigation cases. You might have to move this to reddit or other forums that cater to it.

    I'd be interested in how everyday human interaction with everyday things would actually produce samples that weren't damaged in some way.

    I'd add that just by possessing cleaning materials of that nature a person might attract interest, or if caught up in something, have a lot of probable case to weigh against them.
     
    Last edited: Mar 4, 2015
  15. mirimir

    mirimir Registered Member

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    That's rather like using VPNs, Tor and so on, or FDE, right?
     
  16. driekus

    driekus Registered Member

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    Didnt the Supreme Court judgment imply we should be using a hazmat suit if we wanted to keep our material private?
    I wonder what would happen if somebody walked into an airport wearing a hazmat suit?
     
  17. mirimir

    mirimir Registered Member

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  18. noone_particular

    noone_particular Registered Member

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    If it can be made to look like Spandex, it might work for those built like a model. Then there's the rest of us...
     
  19. mirimir

    mirimir Registered Member

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    No, I mean that it would look like skin :)
     
  20. Veeshush

    Veeshush Registered Member

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    Right. However I think this would be a much stronger red flag in the eyes of anyone that doesn't use DNase in their day job, like cleaning up areas where the deceased had died or something (and I'm not even sure if they'd use DNase). Even in one of the last https://en.wikipedia.org/wiki/Better_Call_Saul episodes, they have a scenario where the lawyer is telling his client that even though the blood in the back of his van wasn't from any of the people in his case, he should of cleaned it. So either way, 90% of people are going to assume a person only needs something like this for this kind of stuff. Again, sure software does have own misguided stigmas against it, but... I don't know.

    There was an early Mythbuster episode where they tried to beat a thermal security camera with them covering their bodies in different stuff, which ended up not doing anything after some tests. Which is another point, that the scenarios would have to be tested to find the disadvantages and faults.
     
  21. AlexC

    AlexC Registered Member

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    Creepy...

    imho the type of knowledge being discussed here (how to prevent DNA contamination) will interest something like 99% to criminals and to people who intend to commit some crime, and 1% to privacy enthusiasts. It reveals a much more concrete intention (clear evidence of physical presence somewhere) than the mere use of VPN for internet surfing (than can have many reasons: enterprise use, intelectual property protection, protection of login credentials, etc.)
     
  22. mirimir

    mirimir Registered Member

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    Hey, I like a good challenge :D
     
  23. RockLobster

    RockLobster Registered Member

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    I wonder how long it will be before they start collecting DNA from children in preschool. They already been doing that with fingerprints.
     
  24. deBoetie

    deBoetie Registered Member

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    Pre-school is right, see "Newborn DNA banking"

    https://www.aclu.org/free-speech-technology-and-liberty-womens-rights/newborn-dna-banking

    It's ironic that it's listed under women's rights to the extent that there could be major surprises for the putative father!

    And very very much illustrative of the deep and fundamental privacy problems we have. Perhaps the biggest "tell" is the extent to which the state thinks it can and should be the holder and arbiter of the records (rather than the baby themselves).

    My personal view is that the case for collecting the DNA information at birth is overwhelming because of its ability to reduce the harm of major genetic defects. But this should be a matter between the child and its medical representatives and not available to the state. I think it should also be available to the nominal parents.
     
  25. Yuki2718

    Yuki2718 Registered Member

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    I provided my part of DNA for medical research as I have specific disease. Ofc they promised it won't be used as a way that my PII can be traced or abused in contract, but yes I won't be pleasant if this info was used in other way.
    I'm not sure if I correctly got what deBoetie means thanks to lack of my English reading ability but I think he have a point, as DNA info is quite valuable in many cases strict regulation and proper judicial system is necessary.

    BTW, SDS act as an antagonist against DNase, and another caution is it's not good for your skin, it's as if you always keep shampoo attached to your body. And if I was an agent who want to collect as many DNA data as possible, I will also collect a hair and a bit of saliva where this mixed anti-DNA spray won't help.