Southern blot analysis of the MTG16 gene. Genomic DNAs were digested with EcoRI and hybridized with probe I and II shown in Fig 4. Probe I; the PCR-amplified 434-bp genomic fragment using the primers 124r5R1 and MTG16r5. Probe II; theEagI-EcoRI 2-kb fragment. Rearranged bands (15-kb band derived from der(21) chromosome and 3.7-kb band derived from der(16) chromosome) and germline bands (12 kb) are shown by arrowheads and an arrow, respectively. Lane 1, a human normal leukocyte cell line C496 was used as a control; lane 2, patient no. 1.