Examples of increasing domain coverage on orthologous proteins through evolution. PPI domain length increase (A), loss of the domain-free sequences at orthologous proteins’ N termini (B), C termini (C), and PPI domain insertion (D) that contribute to increased PPI domain coverage through evolution. Each protein is labeled with its SwissProt identifier. A protein’s name suffixed by the abbreviation of its species name is included inside the parentheses. Within each group, orthologous proteins are ordered by taxonomy. Colored blocks stand for different domains and their annotations are listed at the bottom of each figure. PPI domains are indicated in the block-color legend.