Scatter plot of the microarray data.

The data from the microarray are graphed on a scatter plot to visualize variations (or reproducibility) in gene expression between arrays. The values on the X and Y axes of the scatter plot are the normalized signal values for the samples (log2 scaled). The green lines are fold-change lines (the default fold-change value is 2.0). The expression of the genes above the top green line or below the bottom green line differed more than two-fold between the infected and control samples.