This is a valuable paper explaining how and why changes are made to the Gene Ontology and how these changes are incorporated by resources such as UniProt and the impact such changes may have on annotation datasets viewed and used by researchers. The examples and details given are very useful in helping the casual GO user understand curation processes, update mechanisms and the methods for improving/removing both ontology terms and annotations. While this paper focuses on a single resource, UniProt, the information provided will help researchers better understand processes at model organism databases, the GOC and other organizations. It also provides the researcher with a frame of reference to review and understand differences in GO enrichment analyses that can occur with such changes.

Level of interest: An article of outstanding merit and interest in its field

Quality of written English: Acceptable

Statistical review: No, the manuscript does not need to be seen by a statistician.

Declaration of competing interests: I have no competing interests.