Using Glycogen to prec DNA???

Colin Rasmussen crasmussen at
Wed Nov 9 10:54:05 EST 1994

In article <39p5kb$o1c at>, sannis at (Seanna
Annis) wrote:

> I am trying to purify a PCR fragments, around 600 bp from gel.  I can get 
> a decent amount out of the gel, but I lose it during the precipitation 
> step.  I want to use this product for direct cycle sequencing, so yeast 
> tRNA as an aid to precipitating the DNA was suggested to me to be a bad idea.
> I have heard of glycogen used to prec oligonucleotides.  Does anyone know 
> of the right concentration of glycogen to use.  And does it interfer with 
> sequencing afterwards?  Or does anyone know of another method to get a 
> better yield.  
> Thanks.  Seanna    (sannis at

The normal amount to use is about 20 ug per precipitation...Boehringer's
insert sheet gives a suggested value.  The way we purify fragments is to
run them in low melting temp agarose, melt the gel slice and use the
Promega Wizard Clean-up kit to extract the DNA from the gel. The yields
are great and there is on precipitation required at all.


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