Fig. 2.

Tissue expression distribution for disease and essential genes. The tissue expression index (TEI) was calculated for every gene as the fraction of the 79 tissues analyzed by Su et al. (18) in which the gene was detected as expressed. The genes with large indexes are expressed in almost all tissues, whereas the genes with small indexes have a limited expression distribution. Shown are the fractions for disease and essential genes as the function of tissue expression index. The error bars represent SEM.