Annotation Extension

Each annotation in the Gene Ontology (GO) pairs a single gene product identifier to a single term from the ontology. This very powerful format can also restrict the descriptiveness of a specific instance of a function or a sub-cellular location, as there must be a pre-existing (pre-composed) term in the ontology that provides full details of the specific aspects of the function.

Gene Product Information (GPI) Format

Gene Product Information (GPI) format is used to submit gene and gene product information to the GO Consortium. Please note that the GPI companion file for annotation information uses the GPAD file format.

GPI format version

All annotation files must start with a single line denoting the file format. For GPI it is as follows:

!gpi-version: 1.2

GO Qualifiers


Annotation is the process of assigning GO terms to gene products. The annotation data in the GO database is contributed by members of the GO Consortium, and the Consortium is actively encouraging new groups to start contributing annotation. Annotations can be made from published literature where a curator reads and interprets the experiments and results presented in a paper or can be inferred automatically using sequence information or by key word mapping. Details on how to make automatic inferences can be found on the Electronic Annotation page.

GO Annotation Standard Operating Procedures

This page documents some of the standard operating procedures used by members of the GO Consortium during the process of annotation. Please note that these do not represent the best, or only ways to carry out annotation, but are simply a guide to how some groups currently annotate.

GO Acknowledgements

We gratefully acknowledge the many other contributors to GO annotation efforts:

GO Annotation Conventions

Annotation Conventions

This page contains guidelines which apply to all annotation methods and are particularly useful for manual literature-based annotation. More information on annotation can be found in the introduction to GO Annotation Policies and Guidelines and the GO Annotation Standard Operating Procedures.

Cellular Component Ontology Guidelines

The cellular component ontology describes locations, at the levels of subcellular structures and macromolecular complexes. Examples of cellular components include 'nuclear inner membrane', with the synonym 'inner envelope', and the 'ubiquitin ligase complex', with several subtypes of these complexes represented.