Schematic organization of the IIb (and β3) gene locus region. The heavy line near the top indicates the gene locus drawn to scale with the various identified genes indicated. A partial restriction map for several rare restriction enzymes around the IIb gene is also indicated. The restriction sites shown on this map were generated using data from both pulsed-field genomic fragments (above) and BAC, P1, and YAC sequence and restriction analysis (data not shown). A summary of all clones that have been characterized is shown below with the sequenced regions shown matching the genome or in white rather than in gray. This map only focuses on the region surrounding the IIb locus. A complete map of the β3 locus has been previously reported.6,7 49 (All sequences reported here have been registered with GenBank accession no. AF160252).