Comparison of the organization of mouse and human protocadherin gene clusters. Shown are the genomic organization of three closely linked mouse protocadherin gene clusters (A) and comparisons of the genomic organization of mouse and humanPcdhα/CNR (B), Pcdhβ (C), and Pcdhγ (D) gene clusters. The BAC clones used in the sequence analysis are shown below (A). The length of sequences between clusters is also shown in (A). Each gene family contains multiple tandem variable region exons indicated by a vertical color bar: (mauve) Pcdhα variable region exons; (turquoise) Pcdhβ genes; (orange) Pcdhγ-b variable region exons; (green) Pcdhγ-a variable region exons; (yellow) C-type Pcdh variable region exons (present in both the Pcdhα and Pcdhγ gene clusters); (blue) relic or pseudogene variable region sequences (present in all three gene clusters); (pink) constant region exons. Abbreviations: Pcdh, protocadherin; V, variable region; C, constant region; M, mouse; H, human; r, relic; Θ, pseudogene.
