The Mouse Genome Informatics (MGI) Database at The Jackson Laboratory provides a comprehensive public resource about the laboratory mouse. MGI curated data types include gene representation, mapping, expression, gene function, orthology, mutant phenotype, polymorphism data and sequences. Our annotation system combines both computational and manual curation approaches to obtain high quality data representations, all of which are supported by evidence codes and citations. The relational integration of sequence information with existing biological information in MGI enables users to query for sequences using any combination of the biological attributes mentioned above and get results back in a variety of formats. Furthermore, MGI fully incorporates structured vocabularies such as the Gene Ontology (GO), Mammalian Phenotype (MP) Ontology, and the Adult Mouse Anatomy (MA) Ontology, and regularly exchanges data with many major public bioinformatics resources, including NCBI, SWISSPROT, EBI, the GO, and other model organism databases. The MGI database can be accessed at http://www.informatics.jax.org.