(A) The genes that showed the most significant induction or repression during sporulation (a total of 1,116) were ordered so that genes with similar expression patterns were grouped together and so that the order roughly reflected the time of first induction or repression. Changes in mRNA concentrations for each gene, relative to those in cells immediately prior to transfer to sporulation medium, are graphically displayed with a color to represent the quantitative changes as described in Figure 3. Time after transfer to sporulation medium is shown on the horizontal axis. (B) A set of representative genes was chosen from each of these seven expression patterns, and average expression profiles for each set were calculated.