Figure 3. An OBO-Edit ‘Ontology Tree Editor’ view representing similarities in tubule structures and grouped terms describing the development of different types of renal tubules.

Similarities are observed in GO terms representing tubule structures and terms are grouped together describing the development of different types of renal tubules including the Malpighian tubule of insects (using the Gene Ontology file from March 19^th 2012). The [+] icon beside a term denotes that the node is expandable and has further child/grandchild terms; the [−] icon denotes no further child terms; (P) denotes a part_of relationship; (I) denotes an is_a relationship.