Degree distributions and correlations for model PPI networks. (*a*) Comparison of degree distributions for the Ito data set () and a realization of the random linking model. In this case, all orphans from the model graph of 3,200 nodes are connected to one node that does exhibit connections randomly. The line represents a power-law with an exponent of -2. The degrees in this plot are not shifted as they are in . (*b*) The correlation between degrees for in the model of Ito () compared with the model of Uetz (). In this case, the different experiments are represented as independent sampling of values of *K* from a population of proteins with the distribution of *p* values shown in . The Ito model is equivalent to the random linking results in *a*, and the Uetz degrees are taken from its random linking model (the degree distribution for that graph may be found in the supporting information). The linear correlation is 0.04 in this case.

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