As outlined earlier, an objective of OMIM from its beginning as the book MIM has been to catalog the relationship between phene and gene. The organization of MIM/OMIM has evolved to accommodate that fundamental objective of human genetics. Mapping has been important in establishing that relationship and has been comprehensively chronicled in MIM/OMIM. With completion of the sequencing of the human genome, all genes have, in effect, been mapped in terms of their location in the sequence, but many remain to be characterized (“annotated”). The goal now is to relate phenotype to gene function.