RFLP-PCR. Gel electrophoresis of PCR products after CfoI digestion. Lane1: size marker (100 bp). Lane 2: wild type showing 730 bp fragments. Lanes 3-5: 730 bp of uncleaved amplified fragments from samples with S window peak. Note that CfoI cleaves the GCG/C site created by HbA2' in delta gene of hemoglobin.