It is nessesary to apply aseptic technique for PCR? - (May/15/2008 )

I think that the reason I had multiple bands in my PCR products is because of nuclease contamination. The enzyme entered the mixture and cut the DNA in various places, resulting in multiple fragments instead of the just the one bordered by the primers I used. I figured that the nuclease must have come from the contaminating microbes or skin cells from my fingers as I rub my fingers opening and closing the tubes. So whenever I mix the reagents, I do it under the laminar flow, while wearing gloves sprayed with disinfectant.

Is it really nessesary?Or should I just assume instead it's due to the wrong annealing temperature (yeah I got the multiple bands again).

It's a marginal primer, almost always. Perhaps it could be salvaged by adjusting Mg++ concentrations, additives, or annealing temperatures, but life is short. Redesign it. Doing the voodoo dance around the PCR machine is rarely effective. Same with spraying disinfectant and kneeling before the laminar flow cabinet.