Genes with under- but not over-expression phenotypes cluster into individual protein complexes. Genes with essential functions (A), genes required for normal growth in rich media (B), and haploinsufficient genes (C) are arranged amongst protein complexes very differently to the random expectation. In contrast genes with over-expression phenotypes are arranged much more randomly (D). The graphs show the observed number of complexes in each of ten bins defined by the proportion of subunits having each phenotype. These are compared to the expected values (the mean of 100,000 randomisations). ** Bins significantly different from random at a 5% FDR (Benjamini-Hochberg method).