Fig. 3.

Systematic identification of genetic interactions. (A) Generalized DM plot illustrating the distribution of reporter levels in double mutants Δxxx Δyfg plotted against reporter levels in single mutants Δxxx. A red curve traces the typical double mutant reporter level as a function of the single mutant reporter level. The interaction value (π-score) is determined by the difference between the expected and measured UPR levels in a double mutant. Double mutants with unusually high fluorescence (blue dots), typical fluorescence (black dots), or unusually low fluorescence (yellow dots) represent aggravating, no, or alleviating genetic interactions, respectively. Fully masking interactions are found either on the horizontal blue line (Δyfg fully masks Δxxx) or on the diagonal blue line (Δxxx fully masks Δyfg). (B) Hierarchical clustering of a genetic interaction map based on systematic π-score analysis. To the right of the map, functional clusters are labeled (Table S5). Clusters referred to in the text are highlighted in red; those containing novel components are marked in italics.