The Ensembl genome database project, a collaboration between the Wellcome Trust Sanger Institute and the European Bioinformatics Institute (EBI), provides a comprehensive and stable source of automatic annotation for the human genome sequence. It integrates confirmed gene predictions with external data sources and is available as an interactive web site or flat files. Ensembl is also an open-source software project designed to handle large genomes and associated data from sequence analysis to storage and visualization. The project aims to be portable and easy to apply to different organisms and data types, following the spirit of open-source community projects like Linux. Ensembl's gene annotation process includes ab initio predictions, homology, and gene prediction HMMs, with a focus on minimizing false positives. The Ensembl web site offers various views and tools for data analysis, including BLAST and SSAHA search capabilities. The software system is built on a relational database and reusable components, with a core feature being the 'Virtual Contig' object for seamless handling of draft genome data. Ensembl also supports the Distributed Annotation System (DAS) standard, enabling users to view and compare annotations from multiple sources. The project is funded by the Wellcome Trust and EMBL, and it collaborates with other genome communities to annotate additional genomes.The Ensembl genome database project, a collaboration between the Wellcome Trust Sanger Institute and the European Bioinformatics Institute (EBI), provides a comprehensive and stable source of automatic annotation for the human genome sequence. It integrates confirmed gene predictions with external data sources and is available as an interactive web site or flat files. Ensembl is also an open-source software project designed to handle large genomes and associated data from sequence analysis to storage and visualization. The project aims to be portable and easy to apply to different organisms and data types, following the spirit of open-source community projects like Linux. Ensembl's gene annotation process includes ab initio predictions, homology, and gene prediction HMMs, with a focus on minimizing false positives. The Ensembl web site offers various views and tools for data analysis, including BLAST and SSAHA search capabilities. The software system is built on a relational database and reusable components, with a core feature being the 'Virtual Contig' object for seamless handling of draft genome data. Ensembl also supports the Distributed Annotation System (DAS) standard, enabling users to view and compare annotations from multiple sources. The project is funded by the Wellcome Trust and EMBL, and it collaborates with other genome communities to annotate additional genomes.