DMSO vs. raising annealing temp. in PCR

[Michael Morales]

: I am trying to amplify a fragment of about 100 bp but 
: am getting a smear of products with only little of the desired one.
: I am not using too many cycles and have raised the annealing
: temperature to its highest limit.

: DMSO seems to be rather widely used to increase the specificity of PCR, 
: but I have always thought it may be replaced with tricks in annealing/ 
: denaturation temperature and reagent concentrations.

In my experience, PCR conditions a very empirical.  Each template and primer 
pair can present unique problems.  So I guess what I am saying is that it is 
a thing to try, and it will either help or it won't.  There are a lot of 
helpful articles on PCR optimization, E-mail me and I'll send you a list, if 
you want.

Good luck

Mike Morales



: Am I wrong? 
: May DMSO be better in increasing the specificity of PCR (and the yield of 
: the right product) than the other tricks?
: Is anyone with experiences or knowledge willing to share them?

: Timo Hiltunen