Information access is a major challenge for biologists today. Results are pouring in from microarray experiments, more model organisms are being sequenced and results are being used to expedite drug discovery. There is a growing demand to combine information from different sources and across multiple disciplines, such as clinical medicine, pharmacology, and molecular biology. The volume of literature is increasing exponentially, making it almost impossible for biologists to keep up with current research or to find the particular pieces of information that they need. This makes linkage among existing biological information resources a critical problem.

Information resides in the biological literature. It resides in biological databases that distill information on specialized topics. Such databases include genomic databases (Genbanka), model organism databases (FlyBaseb, Mousec, Yeastd) and protein databases (eg, SWISS-PROTe, PIRf). Linking the literature and the databases are nomenclatures and ontologies that provide standardized references to biological entities and topics–eg, gene names and symbols, protein names, and standard terminology for diseases and symptoms or biological function.