DNA "refusing" to be run in agarose gel

Edward E. Diehl mcdon at mc.duke.edu
Fri Aug 25 15:25:31 EST 1995


Kentil, 
   You might also want to add some salt (NaCl) to your samples prior to
loading.  I have observed the same problem using Wizard-prep minipreps and
was able to stop the "suck out" problem by adding one µl of 1M NaCl to the
sample.  I also think that ethanol is a major problem, be sure to dry your
DNA completely prior to restriction enzyme digestion.


> 
> On Fri, 25 Aug 1995, Ketil Thorstensen wrote:
> 
> > Honored contributors to the molbio.methds-reagnts!
> >=20
> > I have a peculiar problem with persuading some of my DNA samples to run i=
> n=20
> > agarose gels.
> >=20
> > When loading DNA samples on agarose gels I have on several occasions obse=
> rved=20
> > a strange (to me) phenomenon: after application of a sample into a well a=
> =20
> > streak of the sample may follow the pipette tip upon withdrawal. When the=
> =20
> > sample in this way comes in contact with the buffer surface, the sample v=
> ery=20
> > rapidly spreads out to cover the entire surface. During this process most=
>  of=20
> > the sample in the well is "sucked" out.
> > There is no recognizable pattern as to what sample this may happen with. =
> It=20
> > is, however, frustrating when precious samples are lost (the last one was=
>  a=20
> > 1.9 kb DNA probe)  :=ED-(
> > Could anyone enlighten me as to what I am observing, and how to prevent=
> =20
> > this from happening again?
> >=20
> > Thank you very much,
> >=20
> > Ketil Thorstensen, Ph.D.
> > Dept. Clinical Chemistry
> > University Hospital
> > Trondheim, Norway
> > =20
> >=20



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