The Gene Ontology (GO) resource turns 20! Check out the latest paper describing this resource. WormBase uses GO to describe the molecular function, cellular localization and the biological processes that a gene is involved in. These annotations are displayed in the Gene Ontology widget on all gene pages in WormBase. The ontology structure including the number of genes annotated to each term can be viewed via tools such as the Ontology Browser. GO Enrichment Analysis can be performed using tools on the GO website. Data files (known as gene association files) of all the GO annotations in the latest WormBase release (note that these are ahead of the live website) across the genome for C. elegans and several other nematode species can be found here on the WormBase FTP site.