Long PCR smear

[mhollowa at epo.som.sunysb.edu]

In article <94163.093714ABW1 at psuvm.psu.edu> Anne Buchanan <ABW1 at psuvm.psu.edu> writes:
> we removed a tube
>from the thermal cycler every 5 cycles to check the effects of number of
>cycles, and the only difference more cycles made was longer and longer smear.

I can't claim much experience with PCR, but I'll put in my two 
cents anyway.  With such a large number of cycles, isn't it 
possible that you're seeing an increase in incomplete strands?  
Perhaps a survey of clone lengths would be a better indicator 
of success. (?)

Mike Holloway
mhollowa at epo.som.sunysb.edu