Genomic organization of pufferfish Hox clusters. Hox paralog group shown along the top and cluster designation at left. Plate and well numbers of PACs as well as their genomic extent are sketched. (Filled squares) Genes present in both S. nephalus and T. rubripes. (Squares with diagonal lines) Genes found in S. nephalus butnot T. rubripes. (Checkered squares) Genes found in T. rubripes butnot S. nephalus. (Empty squares) Pseudogenes.