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

[J. Owen McCall]

xudong huang wrote:
> 
> 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

Note that if your DNA was purified using Qiagen, unless you took special 
care to avoid it, there can be residual ethanol in your samples that 
results in a lowering of sample density and the propensity to float up 
out of the wells.  Just add more loading buffer to increase the density 
of the sample.  

Owen McCall