Expression signature of intronic and protein-coding transcripts in human liver, prostate and kidney. Transcripts with significantly different levels among prostate, kidney and liver samples were selected by a SAM multi-class test (FDR <0.002) combined with an ANOVA test (p ≤ 0.001) and hierarchically clustered as described in the Materials and methods. In each panel the selected transcripts are shown in the lines and sample replicas in the columns. For each line, expression intensities among the three tissues were normalized within each type of probe and colored as a function of the number of standard deviations from the mean value. (a) Tissue expression signature of 419 antisense TIN transcripts. (b) Tissue expression signature of 567 sense TIN transcripts. (c) Tissue expression signature of 431 antisense PIN transcripts. (d) Tissue expression signature of 2,809 protein-coding transcripts.