DNA degradation

Anthony G. Gutierrez tonygt19 at concentric.net
Sat Oct 18 22:55:18 EST 1997

In article <6204uj$a67$1 at news.utu.fi>, mirher at utu.fi wrote:

> Hello!
> Does anyone know how to inhibit DNase activity? I keep genomic DNA 
> samples at 4 C, and after 2 weeks the DNA seemes to degrade so that
> it can't be used for PCR etc...has anyone got same kind of problems,
> i would really need some ideas here! thanks a lot,
> mirkka
Aliquot your freshly isolated genomic DNA into an array of thermocycler tubes and heat them to 95 deg for 10 min in a thermocycler or in a boiling waterbath.  That will kill heat labile DNases. Note: tubes will pop open unless nearly filled or topped w/oil or covered w/ hot bonnet. Store tubes at -20 deg or colder. Use each tube only once. The source of genomic DNA is also the source of DNases and so are you, all the surfaces in your lab and bacterial and fungal spore laden air. If you use an organic phase separation such as phenol/chloroform or a chaotropic  agent in your DNA isolation make sure you remove all traces before trying PCR since they will inactivate TAQ Pol, the same goes for EDTA and other chelating agents. Never store DNA at 4 deg unless it is lyophilized and vacuum sealed.    

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