Online Mendelian Inheritance in Animals (OMIA, https://omia.org) is a freely available curated knowledgebase that contains information and facilitates research on inherited traits and diseases in non-laboratory vertebrate animals. For the past 29 years, OMIA has been used by animal geneticists, breeders, and veterinarians worldwide as a definitive source of information. OMIA has been reciprocally hyperlinked to its human counterpart Online Mendelian Inheritance in Man (OMIM, https://www.omim.org/) since 1997, to facilitate comparative approaches to the investigation of inherited diseases. A recent collaboration with the Monarch Initiative has enabled an expansion of the integration of information on diseases in animals and humans: relevant human disease entries from the Mondo
Disease Ontology (Mondo, https://mondo.monarchinitiative.org/) were included in OMIA entries, and cross-reference to OMIA non-human animal inherited disease terms and associated information (e.g., taxon (species) affected, gene in which there is a germline mutation, and synonyms) were added in Mondo. Also, ontology-based categories (mostly gleaned from the major biological system headers of the Mammalian Phenotype Ontology) and clinical synopses (based on Unified Phenotype Ontology (uPheno2)) are being incorporated into OMIA to facilitate advanced computational analysis. Improved disease data integration via the use of ontologies will facilitate the seamless joint interrogation of available data from humans and all vertebrate animals in research relating to inherited diseases and thus contribute ultimately to a shortening of the diagnostic odyssey currently experienced by humans and animals suffering from rare diseases.