Detection of seven SSCPs. SSCP screening detected polymorphisms in exon 12 in genomic DNA from the ELO heterozygote, four polymorphisms in exon 14, and two polymorphisms in exon 16. Two normal bands (n) visible in wild-type (wt) homozygotes correspond to complementary strands of PCR-amplified DNA. Heterozygosity is reflected by the presence of an additional 1 to 2 bands.