Significant positive correlation between fold change and threshold cycle (C
) values (Spearman rank correlation, R
= 0.874, N = 40, P <0.001). Each data point represents 2-ΔΔCT of quantitative real-time PCR performed on a subset of sequences to verify the robustness of microarray results. Red and blue spots represent down- and upregulated transcripts, respectively. The black spots represent transcripts that were neutral to the treatment.