how to calculate expression when control dont express - (Jun/02/2008 )

I am studying gene expression with Real Time PCR. Usaly I calculate the % in respect of the control group, but now I've mesured genes that control group don't express, I dont know how to calculate it in this case ¿¿?? What I have to do??

Thank U

Pipet.

Can you compare them to a purified plasmid control? Then calculate number of mRNA per cell.

One thing you can do is to make a sample with a mix of all the samples you are using in your study. In this way all the genes are represented (being or not in the control)
You can use this sample as a reference or calibrator.

Hm, I would rather say than the expression in the control group is 0%, compared to the other group.