The eFamily schema is designed to allow the members of the eFamily consortium to exchange domain definitions. As members of the different databases use different underlying data (languages) so we need a way of getting between the co-ordinates systems. MSD are to provide the mapping between the co-ordinates (translator), hence the reason for the incorporation of the mappings into the core of the schema. The entry represents a database entry. This schema is currently designed for domain and mapping entires. This is a free text field that allows someone to attach some sort of documentation to the entry An entity is a single domain definition. In the case of SCOP, there is only one entity per entry, but in the case of Pfam, an entry is a collection of domains/entities. This is a free text field that allows someone to attach some sort of documentation to the entity An entity may not comprise of a single continuous region. This may be used to a chimeric structure or a discontinuous domain Contains a set of residues objects A single residue object. This object can contain information on what the residue is, general annotation, the numbering system and co-ordinate mapping Allows the linking between different co-ordinate systems This allows one to add information to the residues. For example whether it is observed or whether it is an active site residue Allows cross referencing to another database. For example, one may wish to include which the taxon that a mapping or sequence corresponds Defines the database that is being cross mapped to Contains the mapping coordinates. The start end tags refer to the master databse co-ordinates. The tags prefixed with sys refer to the database being mapped to. This is a free text field that allows someone to attach some sort of documentation to the segment