The Gene Ontology (GO) Consortium aims to create a dynamic, controlled vocabulary for describing gene and protein roles across all eukaryotes. This vocabulary is divided into three categories: biological process, molecular function, and cellular component. These ontologies help unify biological knowledge by enabling the transfer of annotations between species based on sequence similarity. The GO project addresses the challenge of interoperability among genomic databases by providing a structured, precise language for describing gene functions. The GO Consortium is a collaboration between three model organism databases: FlyBase, the Mouse Genome Database (MGI), and the Saccharomyces Genome Database (SGD). The goal is to develop a common vocabulary for describing gene and protein roles in any organism. This vocabulary is flexible and dynamic, allowing for updates as new information becomes available. The ontologies are designed to reflect current biological knowledge and guide the organization of new data. The three ontologies are built from a structured, controlled vocabulary. Biological process refers to a biological objective that a gene or gene product contributes to. Molecular function describes the biochemical activity of a gene product. Cellular component refers to the location within a cell where a gene product is active. These ontologies are essential for organizing and querying biological data, especially as the amount of genomic information increases. The GO project has been tested in the annotation of the Drosophila genome, where 50% of genes were annotated using the GO method with minimal human intervention. The ontologies are also used for gene-expression data annotation, especially after clustering experiments by expression patterns. The GO ontologies are stored in a flat file format and are available online. They are continuously updated as new information is added, and they are expected to evolve for many years. The GO concept provides a common vocabulary for annotating homologous gene and protein sequences across multiple organisms, enabling the query and retrieval of genes and proteins based on their shared biology. The ontologies are a work in progress and are essential for maintaining flexibility and allowing evolution along with increased understanding of underlying biology. The distinctions between biological process, molecular function, and cellular component are crucial for the grand unification of biology.The Gene Ontology (GO) Consortium aims to create a dynamic, controlled vocabulary for describing gene and protein roles across all eukaryotes. This vocabulary is divided into three categories: biological process, molecular function, and cellular component. These ontologies help unify biological knowledge by enabling the transfer of annotations between species based on sequence similarity. The GO project addresses the challenge of interoperability among genomic databases by providing a structured, precise language for describing gene functions. The GO Consortium is a collaboration between three model organism databases: FlyBase, the Mouse Genome Database (MGI), and the Saccharomyces Genome Database (SGD). The goal is to develop a common vocabulary for describing gene and protein roles in any organism. This vocabulary is flexible and dynamic, allowing for updates as new information becomes available. The ontologies are designed to reflect current biological knowledge and guide the organization of new data. The three ontologies are built from a structured, controlled vocabulary. Biological process refers to a biological objective that a gene or gene product contributes to. Molecular function describes the biochemical activity of a gene product. Cellular component refers to the location within a cell where a gene product is active. These ontologies are essential for organizing and querying biological data, especially as the amount of genomic information increases. The GO project has been tested in the annotation of the Drosophila genome, where 50% of genes were annotated using the GO method with minimal human intervention. The ontologies are also used for gene-expression data annotation, especially after clustering experiments by expression patterns. The GO ontologies are stored in a flat file format and are available online. They are continuously updated as new information is added, and they are expected to evolve for many years. The GO concept provides a common vocabulary for annotating homologous gene and protein sequences across multiple organisms, enabling the query and retrieval of genes and proteins based on their shared biology. The ontologies are a work in progress and are essential for maintaining flexibility and allowing evolution along with increased understanding of underlying biology. The distinctions between biological process, molecular function, and cellular component are crucial for the grand unification of biology.