Fig. 2

Expression stability values of reference genes analyzed by geNorm software. a Average expression stability measures (M) of reference genes. The x-axis from left to right indicates the ranking of the genes according to their stability; higher M values indicate lower stabilities. b Determination of the suitable number of reference genes required for normalizing. The software calculates the normalization factor from at least two genes, and the V value defines the pair-wise variation between two sequential normalization factors