Genomic and YAC PFGE hybridized to the IIb and β3 probes. Sequential rehybridization of the same filter to the IIb and β3 cDNAs, the EPB3 5′ genomic fragment, a HOX 2b genomic fragment, and the IIb exon 2 5′ and exon 30 3′ genomic fragments. Numbered arrows indicate bands of interest.