Domain architecture and phylogenetic distribution of the PRDM proteins. (A) Domain architecture of the human PRDM paralogs. For each PRDM protein, the corresponding RefSeq Accession Number and additional names are provided. Protein regions longer than 1000 amino acids and with no domains are shown as vertical bars (PRDM2, 1239 amino acids; PRDM15, 1507 amino acids; PRDM16, 12769 amino acids). (B) Distribution of PRDM genes in representatives of metazoans. For each species, the number of PRDM paralogs is reported in brackets. The species highlighted in cyan are vertebrates, those in yellow are invertebrates. FB, family birth; FE, family expansion; GD, gene duplication.