Heatmap of probability distribution slopes. Thirty-two expression data sets of neoplasia versus corresponding normal tissue (and liver cirrhosis versus normal liver, dysplastic liver versus normal liver and ulcerative colitis versus non-inflamed colon) are compared against all 10 DTs. Each comparison is characterized by a four-dimensional vector of slopes derived from the probability distributions (example in top left corner). Two slope values stem from the distribution of upregulated genes on the DT, two are derived from the distribution of downregulated genes (Figure 1). UpE = slope for upregulated genes in the early part of the DT; UpL = slope for upregulated genes in the late part of the DT; DownE = slope for downregulated genes in the early part of the DT; DownL = slope for downregulated genes in the late part of the DT. Red indicates a steep slope (high specificity of up- or downregulated genes for that segment of the DT), green indicates a flat slope (depletion of up- or downregulated genes in that segment).
Naxerova et al. Genome Biology 2008 9:R108 doi:10.1186/gb-2008-9-7-r108