dNTP mixes and smears

Darren M. Stauth stauth at crunch.usgmrl.ksu.edu
Fri Aug 11 09:32:27 EST 1995

In article <40dl48$1js at news.iastate.edu>, rbellin at iastate.edu (Robert M
Bellin) wrote:

> Hello all,
> 	Lately we have noticed a strange thing in our lab.  It seems
> that if we freeze dNTPs as a mix, we get large smears in our PCR
> reactions, even without template present.  But if the dNTPs from the same
> stock vials are frozen separately, and added individually to the PCR
> reactions, no smears result.  We have also noticed this with one
> commercial mixture of dNTPs (which was supplied to us as a mixture).  Has
> anyone else ever seen anything like this?

I've heard several horror stories in this newsgroup about problems with
master mixes of dNTP's--smearing, degredation through several
freeze/thaws,... However I have never personally experienced any problems
of this type.  I keep a 25mM solution of all dNTP's at -20.  I freeze/thaw
this solution daily and it is used for months at a time.  I use promega
dNTP's and store individual dNTP aliquots at -80 then use those to make the
dNTP mix to be stored at -20.  
Darren M. Stauth  stauth at crunch.usgmrl.ksu.edu

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