Scatter plot of gene expression profiles of PPT1 knockout vs. wild-type mouse brain. Each point represents a unique probe set. Y- and X-axis values are expressed as the logarithm of expression intensity for each probe set. (A) All probe sets (a total of 5236) that passed filtering as described under "Materials and Methods" are shown. (B) Probe sets (total of 267) yielding a significant difference (as determined by SAM analysis under "Methods" between the average of the knockout and wild-type classes are shown.