UpSet plot showing the identity of piRNA sequences in the piC-ZNF518B-WDR1 cluster among the 12 vertebrate species. The intersections of piRNA species are indicated by lines linking samples in the lower panel. piRNAs were classified as the same in multiple species if the piRNA length was < 23 nt and had < 1 mismatch, or if the length was > 23 nt and had < 2 mismatches. No mismatches were allowed in the seed region (2-8 nt). GP, guinea pig; GH, golden hamster; CH, Chinese hamster; ZF, zebrafish
