Screen shot of the Mammalian Phenotype (MP) Browser in which the term 'lethality-embryonic/perinatal' was selected. At the top (yellow shading) the term, its synonym and MP unique identifier appear. The number of paths to term (in this case, one) indicates how many paths through the DAG structure can be traversed to reach the term. The main body of the browser page shows the selected term highlighted and within the context of the hierarchical path(s) of the MP Ontology. In this example page, three levels of the hierarchy are visible (Phenotype Ontology, its 34 sub-terms, and the two sub-terms that fall beneath 'lethality-embryonic/perinatal'. The plus sign, appearing for many of the terms on this page, indicates that these terms have additional sub-terms that can be viewed by clicking on the term to expand the view of that portion of the ontology. The number of genotypes and annotations following the term 'lethality-embryonic/perinatal' is a hypertext link to those data. This latter feature will be available in early 2005.