Ancestral Pcdhα paralog subgroups present in coelacanth have been lost in mammals. (A) Maximum likelihood phylogenies of coelacanth and human protocadherin α cluster proteins. Colors indicate paralog subgroups as shown in Figure 1. The subtree of human Pcdhα1-α13 is shown collapsed for clarity. (B) Phylogenetic relationship of zebrafish, coelacanth, human, and mouse PcdhαC and coelacanth Pcdhα1-α10 proteins.