There are three types of design elements. A feature has a position on the array (within some zone), it can be a control feature for other features or controlled by other features. A reporter corresponds to the physical substance synthesized/printed on the array, it can be characterized by one or more biosequence objects which in turn can be characterized by database entries. There can be many features for the same reporter, and features can have one or several mismatches compared to reporter's reference sequence. The third, most abstract kind of design element is a composite sequence. It can have more than one reporter on the same array (e.g., different splice variants) and is characterized by biological characteristics, which are actually again sequences with corresponding database entries. The mapping between reporters and composite sequences is not shown on this diagram, but this is similar to the model of feature-reporter mapping. Also, composite sequences can be aggregated into more abstract composite sequences (also not shown here), e.g., genes of the same functional group etc.