Comparison of the gene expression differences assessed by our heterologous hybridization analysis and by qPCR. A: Expression fold changes of the 11 genes tested by quantitative PCR. These fold changes correspond to SA/NI for the genes up-regulated during the transition from terrestrial to marine life (represented above the x-axis), and to NI/SA for the down-regulated genes (represented below the x-axis). The white bars correspond to the fold changes assessed by microarray and the black bars to the fold changes assessed by quantitative PCR. B: Comparison of the fold changes assed by microarray and by qPCR. Pearson correlation coefficient = 0.68 (p-value = 0.02).