The Gene Ontology (GO) project, launched in 2006, develops and uses structured, controlled vocabularies for gene, gene product, and sequence annotation. The GO Consortium continuously improves the vocabulary, incorporating community input. Many model organism databases contribute annotations using GO terms. The AmiGO browser has been updated to improve access to these annotations. The GO project provides an ontological annotation system that enables biologists to infer knowledge from large datasets. The GO project is a collaborative effort to construct and use ontologies for the biologically meaningful annotation of genes and their products. The GO ontologies cover three key domains: molecular function, biological process, and cellular component. The Sequence Ontology, maintained separately, covers sequence features. The GO project has seen significant improvements in its content over the past two years, including the development of new terms for pathogenic and symbiotic processes. The GO Editorial Office coordinates changes to the ontologies, with input from curators, model organism database annotators, and other community members. Curator Interest Groups help guide the development of GO and ensure consistency within the ontology. The PAMGO Interest Group collaborated with the GO Consortium to develop new terms for pathogenic and symbiotic processes. This collaboration resulted in a final set of terms that incorporated contributions from both groups. The use of GO terms for gene product annotation has increased substantially, with efforts to improve annotation coverage and quality control. Annotation data are now checked for accuracy and consistency, and new groups are being supported in using GO for annotation. The GO Consortium has initiated Annotation Camps to refine annotation practices and improve the accuracy and precision of GO annotations. These camps have helped educate non-members and promote consistency in annotation practices. The GO Consortium provides software tools for navigating and manipulating GO terms and annotations. AmiGO, a web resource, has been enhanced to improve search and browsing capabilities, including the inclusion of synonyms and improved display of search results. GO data are used in various applications, including gene expression analysis and the development of other ontologies. The GO has been adopted by the caBIG initiative for cancer research, enabling the analysis of microarray and proteomic data. The Sequence Ontology (SO) provides terms and relationships for describing biological sequences. SO and SOFA are used to describe annotations of model organism genomes and are integrated with other biological vocabularies. The future of GO includes work on immunology, responses to stimuli, transport, signaling, and neurobiology. The GO Consortium will continue to update annotation datasets and work with new database groups. Software development will enhance AmiGO and provide more up-to-date access to annotations.The Gene Ontology (GO) project, launched in 2006, develops and uses structured, controlled vocabularies for gene, gene product, and sequence annotation. The GO Consortium continuously improves the vocabulary, incorporating community input. Many model organism databases contribute annotations using GO terms. The AmiGO browser has been updated to improve access to these annotations. The GO project provides an ontological annotation system that enables biologists to infer knowledge from large datasets. The GO project is a collaborative effort to construct and use ontologies for the biologically meaningful annotation of genes and their products. The GO ontologies cover three key domains: molecular function, biological process, and cellular component. The Sequence Ontology, maintained separately, covers sequence features. The GO project has seen significant improvements in its content over the past two years, including the development of new terms for pathogenic and symbiotic processes. The GO Editorial Office coordinates changes to the ontologies, with input from curators, model organism database annotators, and other community members. Curator Interest Groups help guide the development of GO and ensure consistency within the ontology. The PAMGO Interest Group collaborated with the GO Consortium to develop new terms for pathogenic and symbiotic processes. This collaboration resulted in a final set of terms that incorporated contributions from both groups. The use of GO terms for gene product annotation has increased substantially, with efforts to improve annotation coverage and quality control. Annotation data are now checked for accuracy and consistency, and new groups are being supported in using GO for annotation. The GO Consortium has initiated Annotation Camps to refine annotation practices and improve the accuracy and precision of GO annotations. These camps have helped educate non-members and promote consistency in annotation practices. The GO Consortium provides software tools for navigating and manipulating GO terms and annotations. AmiGO, a web resource, has been enhanced to improve search and browsing capabilities, including the inclusion of synonyms and improved display of search results. GO data are used in various applications, including gene expression analysis and the development of other ontologies. The GO has been adopted by the caBIG initiative for cancer research, enabling the analysis of microarray and proteomic data. The Sequence Ontology (SO) provides terms and relationships for describing biological sequences. SO and SOFA are used to describe annotations of model organism genomes and are integrated with other biological vocabularies. The future of GO includes work on immunology, responses to stimuli, transport, signaling, and neurobiology. The GO Consortium will continue to update annotation datasets and work with new database groups. Software development will enhance AmiGO and provide more up-to-date access to annotations.