Table 1.
Gene Ontology evidence codes
| Code | Description | Example |
| Direct experimental evidence codes | ||
| IDA | Inferred from Direct Assay | enzyme assays |
| in vitro reconstitution | ||
| immunofluorescence | ||
| cell fractionation | ||
| physical interaction/binding assay | ||
| IGI | Inferred from Genetic Interaction | "traditional" genetic interactions such as suppressors, synthetic lethals, etc. |
| functional complementation | ||
| rescue experiments | ||
| inference about one gene drawn from the phenotype of a mutation in a different gene | ||
| IMP | Inferred from Mutant Phenotype | any gene mutation/knockout |
| overexpression/ectopic expression of wild-type or mutant genes | ||
| anti-sense experiments | ||
| RNAi experiments | ||
| specific protein inhibitors | ||
| polymorphism or allelic variation | ||
| IPI | Inferred from Physical Interaction | 2-hybrid interactions |
| co-purification | ||
| co-immunoprecipitation | ||
| ion/protein binding experiments | ||
| IEP | Inferred from Expression Pattern | transcript levels (e.g. Northerns, microarray data) |
| protein levels (e.g. Western blots) | ||
| Indirect evidence codes | ||
| NAS | Non-traceable Author Statement | Database entries that don't cite a paper |
| TAS | Traceable Author Statement | original experiments are traceable through that article |
| IC | Inferred by Curator | inferred by a curator from other GO annotations |
| IGC | Inferred from Genomic Context | operon structure |
| syntenic regions | ||
| pathway analysis | ||
| genome-scale analysis of processes | ||
| NR | Not Recorded | used for annotations done before curators began tracking evidence types, not used for new annotations |
| ND | No biological Data available | "unknown" molecular function, biological process, cellular component |
| IEA | Inferred from Electronic Annotation | "hits" in sequence similarity searches, if they have not been reviewed by curators; transferred from database records, if not reviewed by curators |
| ISS | Inferred from Sequence or Structural Similarity | sequence similarity (homologue of/most closely related to) |
| recognized domains | ||
| structural similarity | ||
| Southern blotting | ||
| protein features, predicted or observed (e.g. hydrophobicity, sequence composition) | ||
| RCA | Inferred from Reviewed Computational Analysis | predictions based on large-scale experiments (e.g. genome-wide two-hybrid) |
| predictions based on integration of large-scale datasets of several types | ||
| text-based computation (e.g. text mining) | ||