We curate mappings to other resources. The current set of mappings can be found in the source directory on github:

This is an active area! See issue 426 for the latest

SIO Mappings

The Semanticscience Integrated Ontology (SIO) provides a simple, integrated ontology of types and relations for rich description of objects, processes and their attributes.

We maintain a set of equivalence axioms connecting SIO and RO object properties here:


The set may not be complete - requests for additions welcome on the RO tracker.

Differences between RO and SIO relations

The main difference between SIO relations and RO is that RO uses BFO as an upper level ontology. However, RO generally uses a fairly high level largely uncontroversial subset of BFO. The axioms linking to BFO are in a separate imported ontology that could be swapped out if need be.

See ROAndBFO for more details

BioTop Mappings

Wikidata Mappings