Figure 3

The definition of the breadth of expression. This figure consists of two panels identified as a and b. Panel a shows a histogram of all TPM values for human tissues. The following are the characteristics of the distribution: n = 5.566005e + 06, mean = 1.807312e + 01, median = 3.090820e + 00, sd = 317,803, min = 0, max = 348,120. The cutoff of 10 TPM is signified with the red vertical line. The breadth of expression was the fraction of samples in which the gene was “on”, i.e. in which it was transcribed. The tags per-million (TPM) value of ten was accepted by the FANTOM5 consortium as the standard threshold for a gene to be “on” in a given library. We considered alternative cutoffs of TPM = 100 and TPM = 1000 in b which compares the density plots for the breadth of expression (BoE) at the cutoffs of 10, 100, and 1000 TPM (see figure legend). It is clear that cutoffs of 100, and 1000 are too high, resulting in almost no intermediate and housekeeping genes (i.e. genes with BoE > 0.33).