File:Evolution of Perivitellin-2 PV2 pore-forming toxin.png

English: Schematic illustration of the evolution of the MACPF–tachylectin complex in ampullariids. Based on the genomic arrangements of the MACPF and tachylectin genes, the model proposes that a single copy of MACPF–tachylectin complex was present in the common ancestor of ampullariids. Only in the two species of Pomacea has it become highly diversified, with both MACPF-tachylectin genes that are conserved across Ampullariidae, and multiple Pomacea specific MACPF-tachylectin genes that were generated by tandem duplication. The final 1-MACPF and 2-tachylectin configuration is exclusively expressed in the albumen gland of Pomacea and the proteins detected in their eggs. Numbers below and inside gene diagram boxes are scaffold numbers and gene numbers in the scaffold, respectively. For instance, Lanistes nyassanus contains a MACPF gene (Lny_22924_0.25) and a tachylectin gene (Lny_22924_0.27) in scaffold Lny_22924. For P. canaliculata, the chromosome numbers are shown above the gene diagram boxes. More details can be found in Sun et al., 2019 (Rer 8).