O'Really?

The Open Biomedical Ontologies (OBO) are a set of reference ontologies for describing all kinds of biomedical data, see [1-5] for examples. Every year, users and developers of these ontologies gather from around the globe for a workshop at the EBI near Cambridge, UK. Following on from the first workshop last year, the 2nd OBO workshop 2009 is fast approaching.

In preparation, I’ve been revisiting the OBO Foundry documentation, part of which establishes a set of principles for ontology development. I’m wondering how they could be improved because these principles are fundamental to the whole effort. We’ve been using one of the OBO ontologies (called Chemical Entities of Biological Interest (ChEBI)) in the REFINE project to mine data from the PubMed database. OBO Ontologies like ChEBI and the Gene Ontology are really crucial to making sense of the massive data which are now common in biology and medicine – so this is stuff that matters.

The OBO Foundry Principles, a sort of Ten Commandments of Ontology (or Obology if you prefer) currently look something like this (copied directly from obofoundry.org/crit.shtml):

1. The ontology must be open and available to be used by all without any constraint other than (a) its origin must be acknowledged and (b) it is not to be altered and subsequently redistributed under the original name or with the same identifiers.The OBO ontologies are for sharing and are resources for the entire community. For this reason, they must be available to all without any constraint or license on their use or redistribution. However, it is proper that their original source is always credited and that after any external alterations, they must never be redistributed under the same name or with the same identifiers.
2. The ontology is in, or can be expressed in, a common shared syntax. This may be either the OBO syntax, extensions of this syntax, or OWL. The reason for this is that the same tools can then be usefully applied. This facilitates shared software implementations. This criterion is not met in all of the ontologies currently listed, but we are working with the ontology developers to have them available in a common OBO syntax.
3. The ontologies possesses a unique identifier space within the OBO Foundry. The source of a term (i.e. class) from any ontology can be immediately identified by the prefix of the identifier of each term. It is, therefore, important that this prefix be unique.
4. The ontology provider has procedures for identifying distinct successive versions.
5. The ontology has a clearly specified and clearly delineated content. The ontology must be orthogonal to other ontologies already lodged within OBO. The major reason for this principle is to allow two different ontologies, for example anatomy and process, to be combined through additional relationships. These relationships could then be used to constrain when terms could be jointly applied to describe complementary (but distinguishable) perspectives on the same biological or medical entity. As a corollary to this, we would strive for community acceptance of a single ontology for one domain, rather than encouraging rivalry between ontologies.
6. The ontologies include textual definitions for all terms. Many biological and medical terms may be ambiguous, so terms should be defined so that their precise meaning within the context of a particular ontology is clear to a human reader.
7. The ontology uses relations which are unambiguously defined following the pattern of definitions laid down in the OBO Relation Ontology.
8. The ontology is well documented.
9. The ontology has a plurality of independent users.
10. The ontology will be developed collaboratively with other OBO Foundry members.

I’ve been asking all my frolleagues what they think of these principles and have got some lively responses, including some here from Allyson Lister, Mélanie Courtot, Michel Dumontier and Frank Gibson. So what do you think? How could these guidelines be improved? Do you have any specific (and preferably constructive) criticisms of these ambitious (and worthy) goals? Be bold, be brave and be polite. Anything controversial or “off the record” you can email it to me… I’m all ears.

CC-licensed picture above of the Old Smithy (pub) by Loop Oh. Inspired by Michael Ashburner‘s standing OBO joke (Ontolojoke) which goes something like this: Because Barry Smith is one of the leaders of OBO, should the project be called the OBO Smithy or the OBO Foundry? 🙂

References

1. Noy, N., Shah, N., Whetzel, P., Dai, B., Dorf, M., Griffith, N., Jonquet, C., Rubin, D., Storey, M., Chute, C., & Musen, M. (2009). BioPortal: ontologies and integrated data resources at the click of a mouse Nucleic Acids Research DOI: 10.1093/nar/gkp440
2. Côté, R., Jones, P., Apweiler, R., & Hermjakob, H. (2006). The Ontology Lookup Service, a lightweight cross-platform tool for controlled vocabulary queries BMC Bioinformatics, 7 (1) DOI: 10.1186/1471-2105-7-97
3. Smith, B., Ashburner, M., Rosse, C., Bard, J., Bug, W., Ceusters, W., Goldberg, L., Eilbeck, K., Ireland, A., Mungall, C., Leontis, N., Rocca-Serra, P., Ruttenberg, A., Sansone, S., Scheuermann, R., Shah, N., Whetzel, P., & Lewis, S. (2007). The OBO Foundry: coordinated evolution of ontologies to support biomedical data integration Nature Biotechnology, 25 (11), 1251-1255 DOI: 10.1038/nbt1346
4. Smith, B., Ceusters, W., Klagges, B., Köhler, J., Kumar, A., Lomax, J., Mungall, C., Neuhaus, F., Rector, A., & Rosse, C. (2005). Relations in biomedical ontologies Genome Biology, 6 (5) DOI: 10.1186/gb-2005-6-5-r46
5. Bada, M., & Hunter, L. (2008). Identification of OBO nonalignments and its implications for OBO enrichment Bioinformatics, 24 (12), 1448-1455 DOI: 10.1093/bioinformatics/btn194