DNA recovery from gels

Chris Seidel seidel at mendel.berkeley.edu
Sun Jul 16 20:24:41 EST 1995

In article <bicfo.6.3002D512 at flinders.edu.au>, bicfo at flinders.edu.au wrote:
> I'm having truckloads of trouble trying to consistently recover DNA 
> (0.7-1.8kb) from low-melting point agarose gels. I've tried agarase digestion, 

My preferred method is electro-elution from the DNA gel slice to a salt
using a homemade device similar to IBI's electro-eluter. It works very
and with practice 90% recovery from agarose or acrylamide is common. 

However another fast and popular method for DNA extraction from agarose
gels is to use poly-ester aquarium filter floss and an eppendorf tube as
follows: Start with a 0.5 ml eppendorf tube, slice off the cap and
slice the bottom of the tube so that a small hole is made in the
bottom of the tube. Pack a small amount of aquarium filter floss in
the bottom of the tube. Cut your gel slice to the minimum size possible,
and place it on the bed of floss. Place the 0.5 ml tube into a larger
1.5 ml eppendorf tube, and spin it in a microfuge for 30 seconds, full
speed, whatever it takes to dehydrate the gel slice. The DNA follows
the liquid, and so the larger eppendorf tube should catch what flows
through the filter floss and through the small eppendorf tube. The gel
slice should be almost completely gone. since it is almost dry at this

There was a write up about this method in BioTechniques some time ago.
It seems to work well for things on the order of 1500 bp or less, and 
though recoveries are consistently 50-75%, it has an advantage of being
very very rapid, i.e. gel slice to DNA in buffer, 5 minutes.

Aquirium filter floss is available at aquarum stores, lifetime supply
goes for about two bucks. 


(seidel at mendel.berkeley.edu)

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