How to identify lanes on large agarose gels?

[Peter Frank]

WS wrote:

>Hi Peter,
>
>in order to stain the wells, you might add some BSA to your loading
>buffer.

Does BSA stain with ethidium bromide as DNA does? Or how would that
work?

>Another choice would be a fluorescent ruler which you might
>photograph together with the gel.

So far, I used a DNA ladder (ruler) on each side of the gel for
orientation purposes. This worked well for smaller gels but for larger
gels that obviously wasn't enough to make locating of the lanes easy
within the gel. I guess I would have to put some DNA ladder lanes
within the gel, too. Your suggestion with the fluorescent ruler sounds
good. Can you tell me where I can order such rulers?

>Why do you get such strong deviations that you can't re-
>assign the bands to lanes. Too much salt?

Maybe. Or temperature gradients within the gel while it is being run.

Peter