RAPD Problems - Control lanes with bands

[ANTHONY WILSON]

   I've been performing RAPD reactions using primers from the UBC lab 
and have been running a control with the same stock as my tests (Primer, 
taq, buffer, dNTPs, H20) replacing the DNA with sterilized water, yet I am 
consistently getting banding patterns in these lanes WITHOUT DNA...  I have 
replaced the H20, dNTPs, taq and buffer and yet the bands are as strong as 
ever!  Is this a common setup for a control lane?


   These banding patterns differ from reaction to reaction and from primer 
to primer, yet bands appear in control lanes even when some of the test 
lanes are clean...  Has anyone had any similar experiences and/or any 
suggestions as to where in the protocol this error might be introduced??


   Any help would be greatly appreciated.


Thanks...

Tony Wilson