Figure 3. Determination of the optimal number of reference genes as calculated by geNorm for accurate normalization of gene expression.

Average pairwise variations (V) were calculated by geNorm between the normalization factors NF_n and NF_n+1 to indicate whether inclusion of an extra reference gene would add to the stability of the normalization factor. Values <0.15 indicate that additional genes are not required for the normalization of gene expression.