Analysis of amplified α-spectrin cDNA by acrylamide gel electrophoresis. After amplification of reticulocyte RNA of the region encompassing exons 19-21 of the α-spectrin gene from control (C), the parents (F, M) and the propositus (P), amplification products were analyzed by electrophoresis in a 6% acrylamide gel. The 217-bp expected sized band was observed in the control (C) and both parents (F, M). Two additional bands were also present in both parents and the propositus corresponding to the skipping of exon 20 (124 bp) and the insertion of 12 nucleotides upstream of exon 20 (229 bp).