Hierarchical ANOVA of the putative reference genes. Three-level, nested ANOVA with ‘genes’ as the first level, ‘culture conditions’ as the second level and ‘biological replicates’ as the third level. As in Figure 2, this ANOVA was carried out using different sets of conditions: ‘C sources’ subset (A); ‘Stress’ subset (B); ‘Germination’ subset (C). Left graph: relative expression values (Log (base 2)) as a function of the different conditions for the different genes, taking as the control conditions the glucose sample (A & B subsets) and the T0 time-point for spore germination (C subset). Two values were used for each condition (i.e. duplicated experiment). Right panel: partitioning of the variance into the three levels (in %).