RO is an ontology of relations for use with biological ontologies
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Latest commit 07db785 Mar 23, 2017 @cmungall cmungall new release
 * #145 Moved some axioms to SWRL ensuring RO is valid DL - @balhoff
 * #134, #135, #136, #137, #138, #142, Added new biotic relations for [GloBI]( - @diatomsarecool
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docs docs for branching. See obophenotype/uberon#170 Aug 24, 2016
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el-constraints.owl new release Aug 5, 2015
go-biotic.owl new release Aug 5, 2015
go_mf_import.owl new release Aug 5, 2015
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ro.obo new release Mar 23, 2017
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rohom.owl new release Aug 5, 2015
temporal-intervals.owl new release Aug 5, 2015

DOI Build Status

This is the project page for RO, the new OBO Relations Ontology. This ontology replaces OBO_REL


RO is a collection of relations intended primarily for standardization across ontologies in the OBO Foundry and wider OBO library. It incorporates ROCore upper-level relations such as part of as well as biology-specific relationship types such as develops from.

See the site Menu for more info


Use the following URIs to download this ontology:

Note that the source ontology is OWL - the OBO version may have less axioms. Another difference between the two formats is that the OWL makes use of imports, whereas everything is combined into one with the obo file.


Currently the optimal way to browse RO is to use Protege and inspect ro.owl

See the list of relations on OntoBee -- note that sometimes OntoBee fails to display the full hierarchy

Mail List

Examples of usage

See UsageExamples

Requesting new relations

Use the github issue tracker and/or the obo-relations mail list.

Shortcut Relations

RO includes a number of macro or shortcut relations. E.g

For more information, see Shortcut Relations


RO combines multiple relations from different biological sub-domains into one ontology. Sometimes these relations are very specialized and of limited use outside that domain. For more on extracting specific modules, see:

See RO Modules.

RO replaces OBO_REL

The predecessor of RO was OBO_REL. Many of the relations in OBO_REL have been ceded to BFO. See DifferencesWithOldRO

Coordination with BFO

For details on how RO coordinates with BFO, See ROAndBFO .