Inferred from Direct Assay (IDA)

From GO Wiki
Jump to: navigation, search


  • The IDA evidence code is used to indicate a direct assay was carried out to determine the function, process, or component indicated by the GO term. Curators therefore need to be careful, because an experiment considered as a direct assay for a term from one ontology may be a different kind of evidence for a term from another of the ontologies. In particular, there are more kinds of direct assays for cellular component than for function or process. For example, a fractionation experiment might provide "direct assay" evidence that a gene product is in the nucleus, but "protein interaction" (IPI) evidence for its function or process.
  • For transfection experiments or other experiments where a gene from one organism or tissue is put into a system that is not its normal environment, the annotator should use the author's intent and interpretation of the experiment as a guide as to whether IMP or IDA is appropriate. When the author is using an expression system as a way to investigate the normal function of a gene product, IDA is appropriate.

Examples of IDA usage

  • Types of assays that result in use of IDA:
    • Enzyme assays
    • In vitro reconstitution (e.g. transcription)
    • Immunofluorescence (for Cellular Component)
    • Cell fractionation (for Cellular Component)
    • Physical interaction/binding assay
      • For protein complex membership
      • For 'x binding' annotations when the binding partner 'cannot' be captured in the With (or) From column (GAF Column 8) using a unique accession or identifier. Note, however, that annotations to 'binding' (GO:0005488) or 'protein binding' (GO:0005515) using IDA are not allowed. In those cases, curators should choose, or request a more specific child term.

Table 1. Example annotation where it is not possible to add the interacting partner.

DB Object ID DB Object Symbol GO ID DB:Reference Evidence Code With (or) From
MGI:2137706 Actn1 GO:0051015 (actin filament binding) PMID:15465019 IDA -

  • Assays describing the isolation of a complex by immunoprecipitation of a tagged subunit should use IDA, not IPI. Thus this type of assay can provide IDA for annotation to a component term for the specific complex because it is a direct assay for a complex.
  • Transfections into a cell line, overexpression, or ectopic expression of a gene when the expression system used is considered to be an assay system to address basic, normal functions of gene product even if it would not normally be expressed in that cell type or location. If the experiments were conducted to assess the normal function of the gene and the assay system is believed to reproduce this function, i.e., the authors would consider their experiment to be a direct assay, and not a comparison between various alleles of a gene, then the IDA code should be used.

Examples where the IDA evidence code should not be used

  • Binding assays where it is possible to put an ID corresponding to the specific binding partner that was shown to interact directly the gene product being annotated should be annotated with the IPI code, not with IDA.
  • Overexpression experiments used to assess the effects on function or expression of a gene compared to normal should use the IMP evidence code.
  • Transfection into a cell line, overexpression, or ectopic expression of a gene where the effects of various alleles of a gene are compared to each other or to wild-type. For this type of experiment, annotate using IMP.

Quality Control Checks

Evidence and Conclusion Ontology

ECO:0000314 direct assay evidence used in manual assertion

Review Status

Last reviewed: February 12, 2018

Back to: Guide to GO Evidence Codes