Isolating High MW DNA from Gel- Best Way??

Tony Hodge tph at mrc-lmb.cam.ac.uk
Thu Mar 17 03:53:04 EST 1994


In article <2lq4ea$kh0 at quartz.ucs.ualberta.ca> Andrew Simmonds,
asimmond at gpu.srv.ualberta.ca writes:
>One problem with Geneclean is that the glass fines tend to break up
large 
>fragments of DNA due to the DNA binding to multiple glass beads and 
>basically being pulled apart during re-suspention of the glass/DNA 
>mixture...(I seem to remember a disclaimer to that fact on the
Geneclean 
>documentation).  One improvement I have seen on this technique is
to use 
>a cartridge/insert, (orginally developed by Millipore?) that is
basically 
>a glass filter arranged in such a way that you can run the DNA
mixture 
>through it and have it adhere without the problems associated with
a 
>glass powder.  It is marketed as a kit in Canada under such names
as 
>Glassmax(Gibco/BRL) etc.
>(I don't work for either firm, just use their stuff....)  



Subject: Re: DNA from Gel - GeneClean
From: Mark Jason Logan, mjlogan at whale.st.usm.edu
Date: 15 Mar 1994 23:40:12 GMT
In article <2m5h0s$mku at server.st.usm.edu> Mark Jason Logan,
mjlogan at whale.st.usm.edu writes:
>I think you may run into some problems trying to remove large
pieces of
>DNA from agarose with GENEClean.  You will end up shearing much of
your
>DNA in the process.  I think there is some mention of this in the
>GeneClean manual.  Shearing occurs when the DNA is large enough to
bridge
>more than one surface (bead, whatever).  For moderate sized pieces
of DNA
>this is the way to go.



This is true but only claimed to be a problem for >15kb (see
original post).  I have used GeneClean to clean up Lambda DNA before
now out of desperation (before other products were available) and
got decent clonable DNA.  Basically you do the NEW washes very!
carefully not worrying about re-suspending all the pellet every
time, doing a gently mix when eluting and elute twice.


Tony


.
Tony P Hodge
Structural Studies Division
Medical Research Council Laboratory of Molecular Biology
Hills Road
Cambridge
CB2  2QH
UK

Phone (0223)  402260

Fax     (0223)  213556



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