Heteroduplex analysis of amplified exon 8 DNA. The mixture of the patient's and a normal subject's amplified DNA was run on the first lane on the right. Amplified normal exon 8 DNA was run as a control (second from right). The unmixed amplified DNA from the patient, her immediate family members, and normal control were also run on the same gel as indicated by the pedigree. The position of heteroduplexes (between normal and 3-bp deleted strands) and the length of homoduplexes (both normal and mutant alleles) are indicated. The genetic transmission of the 3-bp deletion is shown. The symbols for male (□) and female (○) are hatched according to the alleles present.