Freeze and squeeze

[Michael Kloth]

celer at brno.ics.muni.cz (Celer Vladimir) wrote:
>
> Hello,
> I need to recover the plasmid DNA ( 6000 b.p.) from agarose gels.
> What is the freeze and squeeze method? What are the advantages of this method
> over phenol-chloroform extraction? Can you help me?
> Thanks fot the help.


Quite simply, you cut out the band of interest and put it
onto a piece of parafilm.  Freeze the band for 20-30 min
at -20, then melt the gel between your fingers, collecting
the DNA in a clean eppendorff tube.  The only things to look
out for are 1) wear gloves, 2) use a TAE buffer system (the 
acetate for some reason enhances recovery) and 3) use a low
melting point agarose.  After collecting the DNA, precipitate
it using potassium acetate and ethanol.

All  in all, it is simple and easy.  A typical yield is 
between 60 and 80%.