Plots of normalized, log2-transformed hybridization intensities within (A and B) and between (C) species. The plots in panels A and B are derived from replicate arrays within each species, and the plot in panel C is the mean across the 3 arrays for each species. The intensities for each gene are color-coded based on the absolute values of the fold difference in transcript abundance as follows: black, ≤2-fold; blue, between 2- and 4-fold; red, ≥4-fold. RMA, robust multiarray average.