Fig. 2.

Joint dependence of gene dispensability on connectivity within the protein interaction network and on expression similarity among paralogs. (A) Proportion of dispensable genes from the total set of paralogs is shown (blue, low proportion of dispensable genes and red, high proportion of dispensable genes) as a function of their degree of connectivity in the protein interaction network and the expression similarity between the paralogous pair members. A version including also the relatively few negatively correlated duplicate pairs is qualitatively similar, although with less statistical power (see SI Fig. 7). (B) P values (plotted in red) illustrating the association between degree connectivity and dispensability were tested for paralogous pair populations and stratified according to expression similarity. These are compared with the P values (plotted in black) illustrating the enrichment of functionally redundant paralogs. The plot was generated by sliding a window of width 0.3, along the expression similarity axis. For statistical details on P value calculations, see Materials and Methods.