Protein centrality in PPI networks has been correlated with evolutionary rate and essentiality of genes in several species (Hahn and Kern, 2005). Proteins that are more central in PPI networks tend to evolve more slowly and be more essential. As shown above, CNV genes show a tendency to evolve more rapidly and are under reduced selective constraint. Therefore, it follows that the products of genes overlapped by CNV may be less central in PPI networks.