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Thread: DNA from 25 year old blood

  1. #1
    practical experience, FTW sprogspasser's Avatar
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    DNA from 25 year old blood

    Hi All.

    MY MC has found a journal that he suspects may have been his father's. The last entry talks of another character having beaten him. There is some blood on the page. The journal was written 25 years ago.

    Question is whether DNA information can be lifted from the dried blood on the page?
    How you spend your days is how you spend your years

  2. #2
    Benefactor Member WeaselFire's Avatar
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    Stranger things have happened.

    There are a million things that can degrade the sample, but if it's large enough, and hot contaminated, it could be done. The question in all of DNA analysis is, what do you have to compare it to?

    Jeff

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    practical experience, FTW sprogspasser's Avatar
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    The question in all of DNA analysis is, what do you have to compare it to?
    MC wants to use DNA to find out if he is the natural son of the journal writer.

    Hot contaminated?
    How you spend your days is how you spend your years

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    Quote Originally Posted by sprogspasser View Post
    MC wants to use DNA to find out if he is the natural son of the journal writer.

    Hot contaminated?
    My guess is this is a typo - should have been 'NOT' instead of 'HOT'.

    As far as the original question - I'm not an expert, but if DNA in amber millions of years ago was acceptable enough to make new dinosaurs, I would think it's possible.

  5. #5
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    Fair samples of DNA have been extracted from bones that were thousands, or even milllions, of years old. DNA is a tough molecule, so twenty-five years probably wouldn't have destroyed it. Determining whose blood it was might be difficult.

  6. #6
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    The backbone of DNA makes it pretty stable. For a paternity test you don't need perfect DNA, you just need the DNA of the small portion (or several small portions) to be intact. If the journal was not kept in extreme conditions, you can probably get the information you need from the sample.
    In addition to degraded DNA, the other problem might be contamination. The tests are very sensitive, and if the MC has been handling the journal, there could be an issue with his DNA contaminating the sample.

  7. #7
    Attack of the Hurricane Turtles! MagicWriter's Avatar
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    Quote Originally Posted by sprogspasser View Post
    Hi All.

    MY MC has found a journal that he suspects may have been his father's. The last entry talks of another character having beaten him. There is some blood on the page. The journal was written 25 years ago.

    Question is whether DNA information can be lifted from the dried blood on the page?
    The science behind it - there would not be enough DNA available off that journal for the character to have it tested, DNA is not found in red cells, the white cells would be isolated and broke down to get the DNA out of them, for testing. DNA is a very hardy molecule, it is very likely that its still in tact. What would need to happen, is the sample would have to go through isolation and PCR (pulling the DNA out of the white cells, and photocopying it), until you have enough to use it for testing. This is where contamination can occur. If any other organism's DNA gets in there by mistake, you will also be copying their DNA as well. Good example is the movie, The Fly, when Jeff Goldbloom goes in that pod, and that fly gets in the pod and becomes a part of him, (I'm trying to create a visual for you). And this will give false results.

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    Attack of the Hurricane Turtles! MagicWriter's Avatar
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    Quote Originally Posted by sprogspasser View Post
    MC wants to use DNA to find out if he is the natural son of the journal writer.

    Hot contaminated?
    Just saw this. The character could find this out by checking blood type records first. If those results are inconclusive, then go to DNA.

  9. #9
    practical experience, FTW cornflake's Avatar
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    If you're looking for an excuse to have something that has DNA to test against, blood isn't your best bet.

    A t-shirt generally contains more testable DNA than a toothbrush, for instance. A hairbrush is often a good source (hair with follicle ends attached are good), etc. I'm not sure how well it's extractable given your timeframe but I think it's likely a better way to go than the blood.

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    practical experience, FTW sprogspasser's Avatar
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    Thanks everyone.

    Journal is only thing MC has from father. Will add a cloth bookmark to the journal (the type that is attached to the journal). Bookmark will have dried blood. Hopefully this will give enough blood for DNA extraction. Will make sure MC is aware not to contaminate.

    Hair already used to identify mother
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  11. #11
    practical experience, FTW cornflake's Avatar
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    Quote Originally Posted by sprogspasser View Post
    Thanks everyone.

    Journal is only thing MC has from father. Will add a cloth bookmark to the journal (the type that is attached to the journal). Bookmark will have dried blood. Hopefully this will give enough blood for DNA extraction. Will make sure MC is aware not to contaminate.

    Hair already used to identify mother
    There's no one related to his father alive?

  12. #12
    pretending to be awake onesecondglance's Avatar
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    Could you not alter the thing with his mother to a toothbrush or something?

    That way you could have an eyelash hair or something in the journal.
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  13. #13
    practical experience, FTW sprogspasser's Avatar
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    There's no one related to his father alive?
    This is worth investigating. I feel a subplot coming up! Thanks!

    Could you not alter the thing with his mother to a toothbrush or something?

    That way you could have an eyelash hair or something in the journal.
    Need to show that father was severely beaten up. The blood is on last entry in the journal.
    How you spend your days is how you spend your years

  14. #14
    pretending to be awake onesecondglance's Avatar
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    Quote Originally Posted by sprogspasser View Post
    This is worth investigating. I feel a subplot coming up! Thanks!



    Need to show that father was severely beaten up. The blood is on last entry in the journal.
    Bloody fingerprints? Fingerprints can be traced to databases that might give you other clues to follow.
    Λrchangel: near-future SF noir
    Bleed Through: multiverse thriller with a side of vampires. | 42,500 / 100,000 (hey look it went up)

    I write music. | I gave in and joined twitter. | And I have a blog too.

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