TrOn: An Anatomical Ontology for the Beetle Tribolium castaneum
Morphological terms as represented in TrOn are given for three life stages: adult A), pupa B) and first instar larva D). The podomers of the adult walking legs are shown in C). E) Example for the relations is_a and part_of between terms of the ontology. Note that for simplicity not all terms and not all connections are shown. There are several types of appendages, for instance legs and wings. There are two types of wings (elytron and hindwing). The legs are present at all life stages (e.g. adult_leg and larval_leg). Legs are composed of several podomeres (see panel C) and each podomer is part_of a leg. Each life stage has legs which contain podomeres. Hence, the adult_trochanter has several relations: it is_a trochanter and it is_a podomer and it is part_of the adult_leg. In an ontology, is_a relations can be used to infer indirect connections. For instance, the adult_trochanter is_a trochanter. In addition, the trochanter is defined as a podomer. As consequence, also the adult_trochanter is regarded as a podomer although this relation has not been defined directly in the ontology (see red arrow). When implemented in databases, such an ontology can help to make searches more intuitive. A search for “appendage” would reveal datasets, with wing or larval_trochanter phenotypes. A search for datasets affecting podomer or leg would not consider datasets with annotated wings.