 The first "tubby" gene was identified in mice, and proteins that are homologous to tubby are known as "tubby-like proteins" (TULPs).They share a common and characteristic tertiary structure that consists of a beta barrel packed around an alpha helix in the central pore.The gene derives its name from its role in metabolism; mice with a mutated tubby gene develop delayed-onset obesity, sensorineural hearing loss and retinal degeneration.