Strange gel pattern, is EtBr the cause? - (Oct/31/2006 )

Hello everybody,

I am getting a very strange pattern on my elephoresis gels. The gel once loaded seams bright on the top but it fades along and it is impossible to see the lower bands together with the bands from the ladder. I know that EtBr runs at opposite direction from DNA, and I do think that the problem must come from the diffrences in concentration in the buffer and on the gel, but I´ve tried to equalize the concentrations and it still occurs!!!

I am using 1xTAE buffer with EtBr (fresh, made up this moorning) and a 0.7 buffer with EtBr also on it.

thanks in advance!

Sónia

can you add a picture to your post please?