Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Storing human DNA.

  1. Jan 8, 2014 #1
    How would I store human DNA for decades, at room temperature, blood samples and not too invasive methods available. It needs to be 100% undamaged and usable for genome mapping.
  2. jcsd
  3. Jan 9, 2014 #2


    User Avatar

    Staff: Mentor

    I believe for military purposes (identification of bodies) they store blood poured on some kind of (blotting) paper and dried out. There is a printed sheet with form to fill and two empty circles where the blood is poured on to dry. No idea if it is kept at room temperature nor what kind of paper they use, but there is no doubt they have the technology and it is rather simple.
  4. Jan 9, 2014 #3
    I was rather thinking of a DIY method, not that I don't have paper I can drape in blood.
  5. Jan 9, 2014 #4


    User Avatar

    Staff: Mentor

    What is not DIY about putting a drop of blood on the paper?
  6. Jan 9, 2014 #5


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Why would you want to do it?
  7. Jan 9, 2014 #6
    It is suppost to last for decades, not years. I can do a DIY paper but I'm not sure if the blood in the paper will decompose into bacteria waste after decades.
  8. Jan 10, 2014 #7


    User Avatar

    Staff: Mentor

    Ah, so it is good for military for bodies that are recovered after decades, but not good for you. OK, got it.
  9. Jan 10, 2014 #8
    Wikipedia has an article about the dried blood spot method that Borek mentioned:


    And there is a section that explains why DNA remains stable at room temperature and while it sounds plausible, I couldn't find a reference for it:

    And here is an example of the method being employed in a practical setting:


    They used PCR techniques to amplify the genetic material in the dried blood spot sample. In this case, they're testing for viral DNA but I believe the same also applies for human DNA.

    Bacteria need water to grow and reproduce so it probably won't decompose into bacterial waste as long as the sample is completely dry. But DNA, while more stable than RNA, does still decompose over time so just out of interest, I looked into how long it takes for a strand of DNA to degrade and found this article:


    And here is a Nature article that removes all of the technical stuff and explains the important bits:


    Since this DNA was collected from fossils that were probably in contact with groundwater at various points during fossilization and subjected to conditions that aren't exactly conducive for preservation, a DNA sample that is kept completely dry in ideal conditions should last much longer than this. Possibly even indefinitely since it is the reactions with water that are thought to be responsible for most bond degradation in the long run.
    Last edited: Jan 10, 2014
  10. Jan 10, 2014 #9
    Here's another article of interest:


    So basically you have two options if you want to store a DNA sample for decades. You could store it in liquid nitrogen or store it dried. Both techniques will keep the DNA relatively intact for decades. If you do decide to take the dried route, you could also slow down the rate of degradation even further and therefore maximize your chances of retrieving the DNA mostly intact by keeping the sample away from heat, sunlight, humidity, oxygen, etc.
    Last edited: Jan 10, 2014
  11. Jan 10, 2014 #10

    Excellent and professional! you have my thanks.
  12. Jan 10, 2014 #11
    Legal purposes.
  13. Jan 10, 2014 #12
    Are you sure you need to map the whole genome? Rather than trying to sequence everything, it would make far more sense, economically speaking, to only look at specific parts of the genome (e.g. known SNPs or VNTRs) if your goal is to use the DNA to identify individuals and/or gain information about their health.

    On the other hand, the cost of whole genome sequencing is decreasing every year so maybe if you are willing to wait another decade or two for the prices to become affordable, then perhaps the above won't really matter by then.
    Last edited: Jan 10, 2014
  14. Jan 10, 2014 #13


    User Avatar
    Staff Emeritus
    Science Advisor

    If you could provide more detailed information then members will be better able to help you. It may turn out you don't even need to store DNA for years at room temperature to achieve your goal, whatever it is.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook