no bands in PCR reaction analysis - does centrifuge time matter? (Mar/26/2007 )

hi there! silly question here.

I have prepared some DNA for PCR, and I was told to do some centrifugation for DNA extraction. However, I centrifuged it for longer than I have been told by mistake. It was originally, 1 min but I made it to 6 mins in one of the steps. then, I don't have no result in DNA sequencing and the PCR product analyse in gel electrophoresis that done afterwards. the positive and negative control and the protein marker is fine in the PCR analyse, is that the problem of the centrifuge time?

thanks for your time!

PS. one more silly question, in DNA extraction, is that necessary to add binding buffer containing GuSCN to the sample? since I found that this buffer is mainly for RNase inhibition and my supervisor said that it is only necessary when the target product is RNA instead of DNA.

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if you are getting bands even in negative controls that means your PCR stocks are contaminated
best option is that change stocks

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thank you for the reply
i mean, positive and negative control are both fine, that is i get beautiful bands in positive control, and no bands in negative control.
so i think the primer and those reagent is fine, but my sample got something wrong. any ideas?

NB. the OD ratio for the sample is 1.7, and the DNA extracted, i think, can be claimed fine.......
would the Fragment broken while centrifuge?

Thanks!

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