Since July 1995, the European Bioinformatics Institute (EBI) has maintained the Radiation Hybrid database (RHdb; http://www.ebi.ac. uk/RHdb ), a public database for radiation hybrid data. Radiation hybrid mapping is an important technique for determining high resolution maps. Recently, CORBA access has been added to RHdb. The EBI is an Outstation of the European Molecular Biology Laboratory (EMBL).