Why can't extracted DNA be stored in freezers for over two months?

Exactly what the question is i need to write notes about it but so far the only reason i can think of is because it would "die" or become contaminated, but pretty sure that is wrong as alcohol would be used to stop biological functions and enable preservation of DNA strands.

Thanks for any help

3 Answers

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  • Ted K
    Lv 7
    3 weeks ago
    Best answer

    You isolate and purify it away from nucleases, and store it in Tris-EDTA buffer pH 8.0 at low temperature and it can last a L O N G time.  DNA is not like RNA--it is much burlier.  And in "pure" form, it can even stand conditions that are quite harsh:

    I have a friend who was working down in New Orleans.  When Hurricane Katrina hit, his lab had its power knocked out and the building was flooded.  All their -80 freezers went down--it was 4 or 5 months before they could get back in to start cleaning it all up.  All their freezers had been sitting with outside temperatures at over 45 degrees (C), with close to 100% relative humidity.  Big mess.  Everything in the freezers was thawed.  But his DNA constructs--thawed, and sitting at elevated temps for months--were intact and he was able to build his libraries back up within a month.  Of course those were small plasmids, not big, long stretches of genomic DNA, but still--pretty impressive.

  • 3 weeks ago

    You can. And we do. All the time. I have freezers full of patients' DNA. You need to store it in buffer and avoid repeated freeze-thaw cycles, but it's an extremely standard long-term storage method.

  • Zirp
    Lv 7
    3 weeks ago

    Well if it is "extracted"...there won't be anything around it to protect it from hungry bacteria who happen to drop by

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