Figure 1.—

Evolutionary models of functional divergence between duplicate genes. The three neofunctionalization (NF) models differ in the number of ancestral functions retained by the gene that acquires novel functions. The newly proposed subneofunctionalization (SNF) model is a combination of NF and subfunctionalization (SF). Duplicate genes are depicted by open circles and different gene functions are shown by solid squares. Dotted lines link genes with their functions. In this article, we analyze functions of duplicate genes by their protein interaction partners and expression sites.