Genomic coordinates of the genes coding for neuroserpin homologs and flanking genes in metazoans. A vertical dashed line indicates neuroserpin (NEURO) orthologs. The genes coding for orthologs of neuroserpin and PDCD10 are consistently arranged in a head-to-head orientation at least since divergence of vertebrates and sea urchins. Orthologs are represented in identical colors. Serpin paralogs are represented as black arrows. The genes coding for neuroserpin and pancpin (PANC) share the characteristic intron distribution pattern of group 3 serpins maintained at least since the fish/tetrapod split.