RT-PCR analysis in F8. (A) RT-PCR picture in F8 from both the patient (p; showing no product) and his mother (m; with positive product). Different RT-PCR regions of the F8 are indicated by Reg A (exons 1-8), B (exons 8-14), C (exons 14-19), and D (exons 19-26), whereas the nested PCRs are labeled 1 to 8. An internal control for the success of the reverse transcription, in the PBGD gene, is also shown (A, bottom panel). The PBGD control primer used for the RT was included in each of the RT reactions of the F8 gene. The PCRs from the control PBGD gene and the F8 gene were done separately (regions A, B, C, and D correspond to the same regions in the top part of the figure). (B) A schematic diagram showing the relative positions of the informative markers in F8 exon 14, a picture of the 1.7 kb (kilobase) RNA-specific RT-PCR product that covers exon 15 and the polymorphic markers in exon 14 is also shown. (C) Schematic diagram of the intron 22 region showing the 2 nested genes F8A and F8B. The position of the primers used for the reverse transcription (Ex 19/26-4) and the 2 subsequent PCRs are also shown (first PCR, F8B-Ex1-F1/Ex 19/26-3; second PCR, F8B-Ex1-F2/Ex 23/26-R). A representative picture of the RT-PCR product of the F8B is also shown. Primers are listed in Table 1.