The need for a way to represent genes/gene products separately from annotations, as well as the need to use the evidence ontology has lead to the creation of the GPAD (Gene Product Annotation Data) and GPI (Gene Product Information) formats. Whilst GPAD and GPI have been defined for use within the Gene Ontology Consortium for GO annotation, this specification is designed to be reusable for analagous ontology-based annotation - for example, gene phenotype annotation.