I have some issues in Real-time PCR data interpretation.
I would appreciate if somebody helped me in the calculation of standard deviation of deltaCt. I have found in ABI bulletin board that the standard deviation of deltaCt is calculated from the standard deviation of the Cts of the biological replicates (treated and control) by this formula s = (s1^2 + s2^2)^1/2. It doesn't make sense to me, since usually there is a lot of variation among the Cts of the biological replicates. For example, if I had the following data:
C - refers to control treatment (numbers refer to biological replicates)
T - refers to test treatment
Goi - gene of interest
Hous - housekeeping gene
Goi Ct (mean of 3 tech replicates) _25,82__25,21__23,64__21,81__21,26__24,7
Hou Ct (mean of 3 tech replicates)_15,65__15,42__13,86__13,57__13,62__16,7
DeltaCt (goiCt- houCt)___________10,17___9,79___9,78___8,24___7,64___8
It seems more rational to me to calculate the standard deviation of deltaCt from the normalized data, that is, calculate from the own deltaCt, not from the Ct. Am I wrong?
Edited by fhsantanna, 16 October 2009 - 07:22 AM.