Re: Gel Problems

Sheryl Christofferson (sherylc@omrf.ouhsc.edu)
Wed, 03 Feb 1999 13:32:46 -0500

Hello Peter:
I am running a 377XL with 48 tooth comb, using Long Ranger concentrate.
The only time I have had severe problems with lane merging was when the
samples were filtered incorrectly and the column buffer (salts) was dried
down with the sample. Otherwise I have slight overlap at the dye front,
which is not a problem. We forbid our clients to give us DNA in anything
but plain deionized, distilled water.

Good luck.

Sheryl Christofferson
OMRF DNA Sequencing Facility

"Johnson, Mr P" wrote:

> We have recently experienced gels where adjacent lanes merge or overlap
> into each other. This occurs to varying degrees ranging from a slight
> overlap of the lanes to a complete merging where the lanes become
> indistinguishable. For 36 lane gels (seen in only a couple of
> instances) the degree on merging remains consistent throughout the
> entire read length of the gel. In 96 lane gels (seen in about 50% of
> cases) the merging is severe at the low molecular weight region of the
> gel (0-200 bases) but then the lanes diverge as the run proceeds. This
> is definitely not a lane-to-lane leakage issue.
>
> We are using the GeneScan application of the PE Biosystems 377 and are
> using Long Ranger Singels acrylamide.
>
> Has anyone else seen this phenomena before or are there any suggestions
> / theories for causes / cures etc.
>
> Peter Johnson
> UK Forensic Science Service