DMSO in PCR rxns ??

[jie li]

In article <3jmp7g$35k at mserv1.dl.ac.uk>, "Matthias Zeiner"
<mzei at sun0.urz.uni-heidelberg.de> wrote:


> This is, in my experience, especially true for GC-rich templates, ie >75% 
> GC. DMSO seems to lower the Tm of DNA, but this also means that one might 
> have to adjust the annealing temperature. Also, specificity of the PCR can 
> be enhanced, for obvious reasons.
> 
> Matthias Zeiner

Please explain further the obvious reasons.  They are still quite obscure
to me.  Sorry!
                                                         Jie li U of PENN