Figure 4. Analysis of exon 4 of PITX3.  A: The gel of amplification products is shown. The 231 bp band containing the insertion is clearly separated from the 214 bp band. A heteroduplex band can also be seen in heterozygous individuals. –ve stands for the unaffected, control individual. M stands for the molecular weight marker, a HpaII digest of the plasmid pUC19. The bands either side of the amplification products are 190 and 242 bp. The heteroduplex runs with the 331 bp band. B: The sequence of exon 4, containing the insertion, for individual III-5 is shown.