Figure 7
Alternative definition of domains. (a) Dendrogram of domains. S(x) was defined as a set of species whose domains are included in the leaves rooted at x. (b) Example of orthologous branching where S(c1) is a set of mammals and S(c2) is a set of fishes. The divergence at v can be correlated with the divergence of mammals and fishes. (c) Examples of paralogous branching. In the upper case, where S(c1) is a set of mammals and S(c2) is a set of vertebrates, it can be considered that domains are duplicated in mammals but not in other vertebrates. We ignored serial duplication such as in the bottom case.