Extraction of DNA from agarose gels

Yasha Hartberg Yasha at bioch.tamu.edu
Mon Oct 3 07:46:46 EST 1994

In article <GABRE.40.2E87E76D at wwg3.uovs.ac.za>, GABRE at wwg3.uovs.ac.za

> Hi,
> We are currently looking for an efficient and fast method for the isolation 
> of DNA fragments from agarose gels.  We experienced problems using low 
> melting point agarose and was looking for a method where one can use normal 
> agarose.
> thanx
>   Gabre Kemp
Here are two methods we use in the lab.

One quick way is to simply sandwich your agarose containing the band
between two sheets of parafilm and stick it in the freezer.  Once the
agarose has frozen, you simply squeeze on the parafilm and your DNA and
buffer come out of the gel.  Yield with this technique is typically a
little low but it works well when you're in a hurry.

One very efficient way of extracting your DNA from the gel is to place the
fragment in a bit of dialysis tubing along with some buffer, clamp both
ends, and electrophorese for about an hour.  To insure that no DNA is stuck
to the sides of the tubing, reverse the leads and electrophorese for five
to ten minutes.  Remove the buffer to a microcentrifuge tube, pp't with
EtOH, dry pellet, and resuspend in dH2O or buffer.

There are also quite a few commercial columns available that work quite
well, but they do cost money.  

Yasha Hartberg
Texas A&M University
"If people want to spend their whole lives creaming and tweezing and
brushing and tilting and gluing, that's really okay too, because it gives
them something to do."  Andy Warhol

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