Simplified hypothesis for the origin, duplication and divergence of vertebrate stomatin subfamilies. An ancestral stomatin gene, possibly present in the last universal common ancestor, duplicated to give rise to eoslipin and prokaryotic paraslipin. Prokaryotic paraslipin was transferred into eukaryotes during the acquisition of the mitochondrion. Eukaryotic slipins probably evolved from eoslipin, which we assume was present in the last common ancestor of all eukaryotes. Within metazoa, slipin-1 arose from a gene duplication (GD) event involving a stomatin-like gene which subsequently fused (GF) with a sterol carrier domain (Edqvist and Blomqvist 2006). Podocin and slipin-3 arose from two further duplications of an ancestral stomatin-like gene that might have occurred during the two whole genome duplications in early vertebrate evolution.