I am having great difficulty getting the 2nd round PCRs (where I add the 454 fusion tailed primers to my template specific primers using an M13 primer tail) working effectively. I generally get a very low amount of PCR product that is often a smear. I have been gel purifying the 1st round add trying a variety of PCR protocols and profiles (adding 150ng 1st round template and PCRing for 4 cycles and also just adding 1ul and PCRing for 15 cycles), but nothing seems to work. Does anyone have a protocol that works for this step?
I am also concerned that the overhanging "A" added by the taq polymerase may be a issue for annealing of fusion tailed primers. Has anybody found the type polymerase has an effect? I have tried Bio-act short mix and Roche's FastStart.
Any advice would be most welcome!
I am also concerned that the overhanging "A" added by the taq polymerase may be a issue for annealing of fusion tailed primers. Has anybody found the type polymerase has an effect? I have tried Bio-act short mix and Roche's FastStart.
Any advice would be most welcome!
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