Figure 1From: Logical Development of the Cell OntologyOntologies and relationships used in computable definitions. (a) Ovals indicate the OBO Foundry ontologies whose classes are used in computable definitions with the CL. Arrows indicate the relationships used with a given ontology. The Protein Ontology and the cellular component of the Gene Ontology both use the 6 relationships describing expression. (b) Graphical representation of how cross product classes are used to define a natural killer cell type.Back to article page