Evidence Codes for the Gene Ontology (GO)
This table presents the evidence codes used by the Gene OntologyTM Consortium, with examples of the types of experiments, data, or statements that are included by each code. The evidence code is linked with a specific GO annotation and literature reference to describe what type of evidence was present in that reference to make the annotation. Additional information about the GO Evidence Codes is available in documentation on the GO site, in GO Evidence Codes.
Code Definition Examples
IC Inferred By Curator
IDA Inferred from Direct Assay
  • Enzyme assays
  • In vitro reconstitution
  • Immunofluorescence
  • Cell fractionation
  • Physical interaction/binding assay.
IEA Inferred from Electronic Annotation
  • Annotations based on "hits" in sequence similarity searches, if not curator-reviewed. Annotations transferred from database records, if not curator-reviewed.
IEP Inferred from Expression Pattern
  • Transcript levels [e.g. Northerns, microarray data]
  • Protein levels [e.g. Western blots].
IGI Inferred from Genetic Interaction
  • Traditional genetic interactions such as suppressors, synthetic lethals, etc.
  • Functional complementation
  • Rescue experiments.
IMP Inferred from Mutant Phenotype
  • Any gene mutation/knockout
  • Overexpression/ectopic expression of wild-type or mutant genes
  • Anti-sense experiments
  • Specific protein inhibitors.
IPI Inferred from Physical Interaction
  • 2-hybrid interactions
  • Co-purification
  • Co-immunoprecipitation
  • Ion/protein binding experiments.
ISS Inferred from Sequence or structural Similarity
  • Sequence similarity [homolog of/most closely related to]
  • Recognized domains
  • Structural similarity
  • Southern blotting.
NAS Non-traceable Author Statement
  • Database entries that do not cite a paper [e.g. SwissProt records, YPD protein reports]
  • Statements in papers [abstract, introduction, or discussion] that a curator cannot trace to another publication.
ND No Biological Data Available
NR Not Recorded
  • Used for annotations done before the DICTYBASE curators began tracking evidence types. It should not be used for new annotations.
RCA Inferred from Reviewed Computational Analysis
TAS Traceable Author Statement
  • Anything in a review article where the original experiments are traceable through that article, or in a textbook or dictionary [e.g. "everybody" knows that enolase is a glycolytic enzyme].