No biological Data available (ND) evidence code

Overview

The ND evidence code is used for annotations when information about the molecular function, biological process, or cellular component of the gene or gene product being annotated is not available.

Use of the ND evidence code specifically indicates that a curator has looked but not been able to find information that supports making an annotation to any term from the Molecular Function, Biological Process, or Cellular Component as of the annotation date indicated.

Note that use of the ND evidence code with an annotation to one of the root nodes to indicate lack of knowledge in that aspect makes a statement about the lack of knowledge only with respect to that particular aspect of the ontology. Use of the ND evidence code to indicate lack of knowledge in one particular aspect does not make any statement about the availability of knowledge or evidence in the other GO aspects.

Note also that it is possible that papers exist that mention the gene, without characterizing it at a level which is relevant for GO annotation. Examples of those types of paper include descriptions of cloning of the gene, disease association studies or usage as a biomarker. None of this data provides material for GO annotations, so a ND annotation is still recommended in this case. If the curation tool you use allows it, mark the paper as 'not suitable for annotation' (blacklist).

ND should be used only for annotations to the root terms, Molecular Function (GO:0003674), Biological Process (GO:0008150), or Cellular Component (GO:0005575), which, when used in annotations, indicates that no knowledge is available about a gene product in that aspect of GO.

Note: The ND evidence code, unlike other evidence codes, should be considered as a code that indicates curation status/progress than as method used to derive an annotation.

When a gene product is annotated to a GO term using the NOT qualifier, this is a statement that it is not appropriate to associate that specific GO term with that particular gene product. However, such a negative annotation does not make any positive statements about the role of that gene product. Thus, there should always be a positive annotation, in addition to the NOT annotation. If nothing is known about the role of the gene product in a given aspect (molecular function, biological process, or cellular component) of GO, then the positive annotation should be made to the root node for that aspect using the ND evidence code.

Annotations made with the ND evidence code are required to use the GO_REF:0000015 reference that explains that curators looked but found no information.

Note that some groups check only published literature while other groups also make sequence comparisons to see if an annotation can be made on the basis of a sequence comparison. The GO Reference collection includes a reference that can be used with ND when both literature and sequence have been checked; to use it, put it in the reference column of a gene association file.

Even if an author states in a paper that there is no data available or nothing is known about the gene product in a particular GO aspect, annotation to the corresponding root node should be made with ND evidence code citing either the annotating group's internal reference or the GOC's reference on use of the ND evidence code, not a specific paper.

DB Object ID	DB Object Symbol	GO ID	DB:Reference	Evidence Code	With (or) From
PomBase:SPBC31F10.17c	na	GO:0008150 (biological_process)	GO_REF:0000015	ND	na
PomBase:SPBC31F10.17c	na	GO:0003674 (molecular_function)	GO_REF:0000015	ND	na
PomBase:SPCC594.01	na	GO:0005575 (cellular_component)	GO_REF:0000015	ND	na

When applying gene product-to-term relations for root node annotations made with the ND evidence code, the following relations should be used:

GO Term Label	GO Term ID	RO Term for GAF 2.2	RO term ID
biological_process	GO:0008150	involved_in	RO:0002331
molecular_function	GO:0003674	enables	RO:0002327
cellular_component	GO:0005575	is_active_in	RO:0002432

Last reviewed: April 12, 2018