Jim,
it does sound like he is having uneven polymerization that can be due to a
non-level surface where he is casting his gels. Maybe too that the power
supply is not consistant at the bottom of the gel. I don't know if that is
possible, but if so, then the DNA is all going to the point of the gel
where there is a strong positive pull, or where the power supply is
stronger. Also, I have read that people's lanes skew to a point (I don't
know if they are getting overlapping DNA) but this happens when their
Formamide has gone bad or they have high salt concentrations in their
reactions.
___________________________________________________________________
Andrea N. Molinaro
Laboratory of MicroChemistry
Lindsley F. Kimball Research Institute
The New York Blood Center
310 E. 67th S.
New York, NY 10021
phone: (212) 570-3188
molinaro@nybc.org