PCR variability with DNA extraction method

[benedicte Shevchenko]

Hello

I had the same problem of PCR band disappearance after extraction of DNA 
from blood using Quiagen extration kit. In fact latter I read that 
Hemoglobine which some time contaminates samples is an inhibitor of DNA 
polymerase. And it's necessary to heat PCR mixture-samples at 94 C for 
10 to 15 min prior addition of nucleotides and enzyme. When I did this, 
suddenly the bands appeared. So when you boiled your samples I suppose 
you distroy the hemoglobine and then your PCR reaction is good.
In fact recently I shift from quiagen and I use a kit from DYNAL : 
Dynabeads DNA direct kit. It's very easy to use and I never had problem 
of PCR inhibition after DNA preparation. I even never need to boild my 
samples anymore.
Hope this can help you.

Bene.