Gene associations between entities and GO terms are saved by the Gene Ontology consortium to large annotation files in a simple file format, available at the link below:
http://www.geneontology.org/GO.current.annotations.shtml
Annotation files are divided up by species and are used to create automatic Gene Ontology links to lots of different external database resources such as Entrez-Gene.
Moreira et al. (2007) criticised this annotation file format, citing semantic ambiguities inherent to the file structure which could be solved using OWL. A big problem for example is the use of the NOT qualifier, which means that an annotation, often manually curated, specifies that an ontology term is NOT associated with a gene.
So the gene FMN1 in S. cerevisiae (according to QuickGO) is NOT associated with FMN adenylytransferase activity.
- See gene FMN1 (riboflavin kinase) Saccharomyces cerevisiae in QuickGo
The EntrezGene service automatically extracts GO annotations, presumably from recent annotation files. The paper above noted that the FMN1 entry in EntrezGene did not highlight the negative relationship between FMN1 and FMN adenylytransferase activity because it failed to infer the appropriate meaning from the NOT qualifier.
- See the same gene FMN1 in Entrez-Gene
The entry is still labelled with the GO annotation ‘FMN adenylytransferase’ activity, even though PMID 10887197 suggests FMN1 in S. cerevisiae does not display said activity.
This is a problem.
Moreira, D. A., Shah, N. H., and Musen, M. A. (2007). Interpretation errors related to the go annotation file format. AMIA … Annual Symposium proceedings / AMIA Symposium. AMIA Symposium, pages 538-542.

