DNA extraction from gel

Anne Gillen amgillen at ucdavis.edu
Fri Aug 27 21:35:40 EST 1999

> There are kits by Qiagen, Bio101 and probably by many other companies. These
> I know are based on gel solubilization by NaI. High salt concentration make
> DNA bound to silica gel (silica particles, silica membrane or whatever),
> then washing the resin with alcohol and elution with water. These methods
> work well as RNA/DNA extraction methods too if you substitute NaI with
> GuSCN.
> Cheers,
> Tomek


I know this may sound like nit picking, but I once had someone tell me in all
seriousness that you did not need NaI to use the gene clean on PCR fragments
(Sometimes I use the kit to clean up PCR, not bands in agarose) because it is
only needed to solubilize the agarose.  This is not so.  I looked up the
original paper and it said that NaI, or other chaotropic ions, are needed to
bind DNA to the silica.  Once the DNA is bound you no longer need the NaI to
maintain the bond.


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