Storage/stability of DNA

Mike Dalrymple dalrymple at
Fri Nov 3 05:52:14 EST 1995

In article <DHGorC.FyA at> Dr David E Barton,
dbarton at writes:
>Subject: Re: Storage/stability of DNA
>From: Dr David E Barton, dbarton at
>Date: Fri, 3 Nov 1995 09:52:23 GMT
>>Query posted regarding degrading DNA
>>>We would like to be able to keep the DNA samples for at least several
>>>years without significant degradation.  Any comments or suggestions
>>>regarding suitable storage techniques would be appreciated.
>It seems unlikely that your DNA is actually degrading during storage at -70C.
>Try heating the DNA to 65C for 15min to kill any nucleases before adding any
>restriction enzyme buffer. In my experience, once you add the RE buffer, any
>contaminating nucleases get activated.  The Chloroform idea is also good if you
>must store at 4C, but it is not a permanent solution.
>Best wishes, David.


I recently dug some old plasmid DNA out of the -70 freezer. It had been
there continuosly for nearly six years without being thawed. The material
fine except for one would not cut with any of three or four
enzymes I tried! In the end I re-transformed the plasmid into bugs and
made some
fresh DNA. I do not have an explanation for this observation. The DNA was
before storage. However, as a means of maintaining the integrity of the
DNA, -70 storage
would appear to be a good way of doing it.

Mike Dalrymple

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