UML diagram of the Oligomer concept and related concepts. Each concept is shown as a box, and is named in the top section of the box. All attributes for each concept are listed in the middle section of the box. Arrows represent relationships between concepts, and open-ended arrows indicate "is a" relationships. The relationship of one concept to another is indicated by the text on each arrow. Arrows with [0..*] (zero or more) or [1..*] (one or more) indicate the number of instances of the concept at the end of the arrow that is associated with the concept at the beginning of the arrow. The Oligomer concept is central to the GPCR oligomerization ontology and all other concepts in the ontology relate to it either directly (e.g., Oligomer ''is described by'' IdentificationStudy) or indirectly (e.g., Oligomer ''is composed of'' one or more [1..*] Protein that ''belongs to'' Family).