Vps25N55/ArkH16 mosaics exhibit non-autonomous cell proliferation. Vps25N55/ArkH16 cells undergo apoptosis. Vps25N55/ArkH16 clones cannot be recovered in the adult eye. Vps25N55/ArkH16 clones occupy a large fraction of the eye discs, suggesting that these clones have no intrinsic growth disadvantage over wild-type tissue if cell death is blocked. The adult eye of Vps25N55/ArkH16 mosaics is severely overgrown and folded.