TAS: Traceable Author Statement

Updated November 9, 2007

  • Any statement in an article where the original evidence (experimental results, sequence comparison, etc.) is not directly shown, but is referenced in the article and therefore can be traced to another source.

The TAS evidence code covers author statements that are attributed to a cited source. Typically this type of information comes from review articles. Material from the introductions and discussion sections of non-review papers may also be suitable if another reference is cited as the source of experimental work or analysis.

When annotating with this code the curator should use caution and be aware that authors often cite papers dealing with experiments that were performed in organisms different from the one being discussed in the paper at hand. Thus a problem with the TAS code is that it may turn out from following up the references in the paper that no experiments were performed on the gene in the organism actually being characterized in the primary paper. For this reason we recommend (when time and resources allow) that curators track down the cited paper and annotate directly from the experimental paper using the appropriate experimental evidence code. When this is not possible and it is necessary to annotate from reviews, the TAS code is the appropriate code to use for statements that are associated with a cited reference.

Once an annotation has been made to a given term using an experimental evidence code, we recommend removing any annotations made to the same term using the TAS evidence code.

Note that prior to July 2006, it was allowed to use the TAS evidence code for annotations based on information found in a text book or dictionary; as text book material has often become common knowledge (e.g. "everybody" knows that enolase is a glycolytic enzyme). However, at the 2006 GO Annotation Camp, it was concluded that this sort of information is not traceable to its source and is thus not suitable for the TAS evidence code. When annotating on the basis of common knowledge possessed by the curator, consider the IC code. When annotating an author statement that that is not associated with a cited reference, use the NAS code.

Examples where the TAS evidence code should be used:

  • Annotating the twelve S. cerevisiae genes (RPO21, RPB2, RPB3, RPB4, RPB5, RPO26, RPB7, RPB8, RPB9, RPB10, RPC10, and RPB11) that are part of the core complex of RNA polymerase II to the GO term DNA-directed RNA polymerase II, core complex ; GO:00005665 based on a table in Meyer and Young, 1998 (PMID:9774381) listing each of these genes as encoding a subunit of the enzyme and giving one or more references for each subunit.
  • Annotating the human myo9b gene to the GO term Rho GTPase activator activity ; GO:0005100 based on this statement in the introduction of a research article, Post et al., 2002 (PMID:11801597):
    "Biochemical characterization of both bacterially expressed Myr5 and Myr7 tail domains and tissue-purified human Myo9b demonstrate that these myosins IX are active GAPs for Rho but not Rac or CDC 42 (3,4,7)."

Examples where the TAS evidence code should not be used:

  • In Ladd et al., 2001 (PMID:11158314), the authors state:
    "All of the CELF proteins contain multiple potential protein kinase C and casein kinase II phosphorylation sites. All are predicted to have predominantly nuclear localization, and CELF3, CELF4, and CELF5 each possess a consensus nuclear localization signal sequence near the C terminus."
    As this paper provided no reference to support the author's ascertion that CELF3 is located to the nucleus (nor presentation of sequence analyses related to this statement), and the absence of better published data at the time of curation, CELF3 has been annotated to the GO term nucleus with the NAS evidence code and not the TAS evidence code.


    DB Object ID


    DB Object Symbol




    GO ID




    Evidence Code



    ...   gene B   GO:0005634 PMID:11158314 IGC operon_geneA_ID|operon_geneC_ID (from operon in annotated organism) ...
    ... UniProt:Q5SZQ8 CELF3_HUMAN   GO:0009102 PMID:15347579 NAS   ...
  • When an annotator makes an annotation based on a combination of another GO annotation and common knowledge. For example, if a curator makes an annotation to the cellular component term nucleus on the basis that the gene product is already annotated to the molecular function term general RNA polymerase II transcription factor activity and the common knowledge that transcription factors interacting with RNA polymerase II act in the nucleus, then the IC evidence code should be used with the GO ID for the GO term from which the annotation was derived in the with/from field and the same reference should be cited as was used for the annotation to the term whose GO ID is placed in the with/from field.