Hey, I've been running gels nearly non-stop for the past week or so, and had an unusual problem yesterday, that no one in the lab can fathom!
When I put the gel in the transluminator, I was getting a really bright 'splodge' which at first I thought was due to someone fiddling with the camera settings, or then maybe a lens flare effect or something, but I couldn't get rid of it. I tried placing it on a UV slab for direct visualization, and realized that the splodge was a load of ethidium bromide that had just stuck in that location on the gel for some reason!
I prepared the gel as normal, mixing the EtBr into the molten agarose and swirling thoroughly before casting, so I have not idea why this happened! Anyone have any ideas? My scanner's bust, so I've taken a photo of the photo of the gel and uploaded that.