Distribution of clade B serpin genes in vertebrate genomes. A dendrogram showing relationships between vertebrate species with clade B serpin gene loci. The genes identified within each genome are indicated on the right without the SERPIN root designation. Multiple loci are delineated by square brackets, while genes identified in EST databases, but not in the genome, are in round brackets. * due to the incomplete nature of the sequencing data, the structure of the rabbit (Oryctolagus cuniculus) loci could not be established. Branch lengths are not to scale.