Created by the Jackson Laboratory as part of Mouse Genome Informatics, this website features Mammalian Orthology and Comparative Maps. At this site, searches can be made in the area of Mammalian Orthology by species, gene symbol, name, or map position. Site visitors can also build comparative maps, retrieve an Oxford Grid to display a two-species orthology comparison, and view orthologies between mouse and human or mouse and rat at the whole genome level. The site links to Gene Family Information, MGI Mammalian Orthology Criteria, and MGI Database Reports as well.