Storage/stability of DNA

Mike Dalrymple dalrymple at pplros.demon.co.uk
Fri Nov 3 05:52:14 EST 1995


In article <DHGorC.FyA at news.tcd.ie> Dr David E Barton,
dbarton at acer.gen.tcd.ie writes:
>Subject: Re: Storage/stability of DNA
>From: Dr David E Barton, dbarton at acer.gen.tcd.ie
>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.
>

Hello,

I recently dug some old plasmid DNA out of the -70 freezer. It had been
stored
there continuosly for nearly six years without being thawed. The material
was
fine except for one problem...it would not cut with any of three or four
restriction
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
fine
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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