Deanne Bell dbell at fresno.ars.usda.gov
Tue May 11 13:23:03 EST 2004

There are a lot of things that might be happening.

If you are using a capillary electrophoresis, There are always a lot of
peaks that run through the capillary very early - these are excess
primers.  My gut instinct says that there is something happening with
your primers.

Are you sure this is 75 "BASE PAIR"?  On my machine, the raw data from a
run comes out on a time scale - so the x axis does not get converted
into "base pairs" until you assign a start point for the analysis. 

 And the software will sometimes switch the SCALE of your graph (both
the x and y axes).  When viewing 2 different samples, make sure you are
comparing them at the same scale.

Hope this brings some insight.  If I knew more about your set-up I may
be able to help some more.
Dee Bell

-----Original Message-----
From: owner-methods at hgmp.mrc.ac.uk [mailto:owner-methods at hgmp.mrc.ac.uk]
On Behalf Of emad
Sent: Friday, May 07, 2004 1:34 AM
To: methods at hgmp.mrc.ac.uk
Subject: AFLP

While I am running AFLP with fungal DNA I used water as control in one
run in the selective amplification step then I proceed to the step of
loading in the automated sequencer.
What made me astonished is that the H2O controls produce a pattern of
bands till 75 bp.
Does any one know an explanation for what happened here? 
best regards .
nagref - greece

More information about the Methods mailing list