Figure 4.

Comparison of the fugu (FrPcdh1 and FrPcdh2), zebrafish (DrPcdh1 and DrPcdh2)and coelacanth (LmPcdh) protocadherin clusters. Variable exons in each paralog group are shown in different colors. Orthologs between fugu and zebrafish as well as the inter-locus paralogs between the two Pcdh loci in fugu or zebrafish are shown in the same colors. 'Teleost Pcdh1' and 'Teleost Pcdh2' are the Pcdh clusters predicted in the common ancestor of fugu and zebrafish, and 'Fish Pcdh ancestor' is the single Pcdh cluster predicted in the ray-finned fish prior to the 'fish-specific' whole genome duplication. The corresponding exons in the 'Fish Pcdh ancestor' and the inter-locus paralogs between 'Teleost Pcdh1' and 'Teleost Pcdh2' are shown in the same color except the 'αIV', which represents a common ancestor for fugu FrPcdh2α8–25 and zebrafish DrPcdh2α8–25. Among the exons predicted in the 'Fish Pcdh ancestor', those present in the Pcdh loci of both fugu and zebrafish are labeled with an asterisk.