NAS: Non-traceable Author Statement

Updated November 9, 2007

  • Database entries that don't cite a paper (e.g. UniProt Knowledgebase records, YPD protein reports)
  • Statements in papers (abstract, introduction, or discussion) that a curator cannot trace to another publication

The NAS evidence code should be used in all cases where the author makes a statement that a curator wants to capture but for which there are neither results presented nor a specific reference cited in the source used to make the annotation. The source of the information may be peer reviewed papers, textbooks, or database records. For some annotations using the NAS code, there will not be an entry in the with/from field.

The NAS code is also used for making annotations from database entries when a curator reviews the annotations that result. Typically such annotations will refer to an unpublished reference describing what was done, either a reference with a GO_REF id or an internal reference from the specific annotating database.

Cases where the NAS code should be used:

  • In Ladd et al., 2001 (PMID:11158314), the authors state that:
    "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.


    DB Object ID


    DB Object Symbol




    GO ID




    Evidence Code



    ... UniProt:Q5SZQ8 CELF3_HUMAN   GO:0009102 PMID:11158314 NAS   ...

Cases where the NAS code should not be used:

  • When an author makes a statement that is attributed to a source cited in the reference list, use the TAS evidence code.
  • 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.