painful gel loading???!!!!!!

natldiagnos at mindspring.com natldiagnos at mindspring.com
Fri Feb 7 11:46:17 EST 1997


Xudong Huang wrote:

Hello,

I have a painful problem about agarose gel loading. The DNA samples do
not stay at the bottom of wells, intead, they float out of wells and
diffuse into the buffer. The loading buffer I use is 6XBPB, the gel
running buffer is 1X TBE. It is not because of air bubbles or oil in the
samples. Could you let me know what is going on? Thank you.

Xudong Huang
email:xudong.huang at endo.mas.lu.se


Xudong,

The most likely explanation for the DNA samples floating out of the
wells is due to residual ethanol in the DNA.

Do your "standards" also come back out of the wells?

Try "completely" drying your DNA pellet prior to redissolving the DNA,
then add your 6XBPB.

The "best" loading dye concentrate for agarose gels is the one made with
Ficoll (see Maniatis'Cloning Manual, or Current Protocols in Molec.
Biol. for the recipe).

For the DNA samples you already have, you may put them in a speed-vac to
remove residual ethanol, add back water, and then try reloading an
aliqout of the samples on your agarose gel.



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