Numbers of functionally related genes undergo changing profiles over the course of the primary response. Gene expression levels were calculated using MAS, RMA, and dChip, normalized using the associated algorithms and filtered using GeneSpring. Genes with more than 4-fold change in expression compared to baseline (0 hours) were selected. Only those genes selected irrespective of normalization method were further analyzed and these genes were grouped according to their known or putative functions. The analysis represents the cumulative numbers of genes at peak expression in each functional group at each time point.