Examples of the evolution of venom components affecting glucose homeostasis include a Glp-1 like gene exendin-4 expressed in the lizard Heloderma suspectum (Gila monster) venom (now underpinning a type 2 diabetes drug14, 15), a fish-like insulin mimetic in cone snail venom16 and the GLP-1 degrading enzyme DPP-4 in venom of various snake species17. This evidence concerns the gene INS and type 2 diabetes mellitus.