Figure 2.
The distribution of genetic interactions supports the duplicate buffering hypothesis. (A) The proportion of negative interactions among screened pairs for duplicate pairs, singleton pairs with a protein–protein interaction (Materials and methods) and random singleton pairs. Error bars represent the error on a binomial proportion (P<5 × 10−23; Binomial proportion test). (B) The proportion of negative interactions among duplicate pairs differs between modes of duplication. Whole-genome duplicates (WGD) exhibit a slightly higher rate of negative interaction than their small-scale duplication (SSD) counterparts (P<5 × 10−2; Wilcoxon rank-sum). The rate of negative interactions within SSD pairs is still much higher than related singletons (Figure 2A), indicating that the functional overlap observed within duplicate pairs is not solely driven by WGD pairs. (C) The number of genetic interactions (both positive and negative) is plotted for all non-essential duplicates and singletons. Genes shown represent those found on the SGA deletion array and thus the counts represent the number of query genes with which a given array gene shows an interaction (see Materials and methods). Means are shown and error bars represent one standard deviation of the mean over 1000 bootstrapped samples of the distribution. (P<6 × 10−16; Wilcoxon rank-sum), (D) Although duplicate genes show far greater profile similarity than random pairs, they show significantly less similarity than physically interacting pairs (P<5 × 10−6; Wilcoxon rank-sum). Median cosine similarity is shown (Materials and methods). Error bars represent the standard deviation of the median over 1000 bootstrapped samples.