Figure 8

Selective pressures on connectivity in protein-protein interaction networks. Error bars represent 95th percentile confidence intervals from bootstrap resampling. (a) Proteins with more interaction partners appear to have lower A/S ratios (gray bars); however, for yeast two-hybrid interactions, the differences are less significant for proteins with at least one interaction partner (white bars). (b) Proteins with more interaction partners tend to have higher mRNA expression levels (gray bars). This could result from experimental bias: for yeast two-hybrid interactions, the differences are not significant for proteins with at least one interaction partner (white bars).