Figure 3.
Global and local genetic interaction similarity comparisons support selection distinction. (A) Profile similarity shown as in Figure 2D. Duplicate pairs have been separated into dosage and non-dosage (divergent) classes (Materials and methods). Divergent duplicates show significantly less profile similarity than either dosage duplicates or singletons showing a physical interaction (P<5 × 10−2; P<1 × 10−3; Wilcoxon rank-sum test). Dosage duplicates are not statistically distinguishable from physically interacting singletons. (B) A hypothetical functional network is shown that contains a duplicate pair (A′/A′′). A proxy gene (P) is identified by finding a protein that shares protein–protein interactions with both duplicates (see Materials and methods), and P is used to approximate the genetic interaction profile of the common ancestor (that is, A). The number of times a duplicate's similarity with its sister exceeded its similarity with P is shown as a percentage, and error bars represent error on a binomial proportion. Dosage and divergent pairs are counted separately. In terms of genetic interaction profiles, divergent pairs more closely resemble their common neighbor than they do each other. In contrast, dosage pairs more closely resemble each other. The probability that these two classes come from the same binomial distribution is small (P<9 × 10−5).