Figure 2
From: Selection of reference genes for quantitative real-time PCR in a rat asphyxial cardiac arrest model
Determination of the optimal number of control genes. The geNORM program was used to analyze the pairwise variation between the normalization factor NFn and NFn+1. Every bar represents change in normalization accuracy when stepwise adding more endogenous controls according to ranking in Fig. 1. Data were analyzed for the three different time points 4 days (A), 7 days (B) and 21 days (C) after ACA. The use of the two most stable genes is in each case sufficient for an accurate normalization (cutoff 0.15 according to [19]). The higher V9/10 is due to the inclusion of a relative unstable gene, B2m, and is in accordance with the average expression stability M.