Comparison of gene expression frequency in monocytes, GM-CSF–, or M-CSF–induced macrophages. A semilogarithmic plot shows 116 and 73 tags that were decreased more than 10 times in GM-CSF– or M-CSF–induced macrophages, respectively, compared with monocytes, whereas 118 and 137 tags increased more than 10 times in GM-CSF– or M-CSF–induced macrophages, respectively, compared with monocytes. Moreover, 21 tags increased more than 10 times in GM-CSF–induced macrophages compared with M-CSF–induced macrophages; 34 tags increased more than 10 times in M-CSF–induced macrophages compared with GM-CSF–induced macrophages; 57,560, 57,463, and 55,856 tags derived from monocytes, GM-CSF–, or M-CSF–induced macrophages, respectively, were used for this analysis. The relative expression of each transcript was determined by dividing the number of tags observed in monocytes or both macrophages, as indicated. To avoid division by 0, we used a tag value of 1 for any tag that was not detectable in one sample. These ratios are plotted on the abscissa. The number of genes comprising each ratio is plotted on the ordinate.