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. 2004 May 20;75(1):44–53. doi: 10.1086/422175

Figure 1.

Figure 1

A polymorphic PvuII site at position 6044 of GenBank accession number AF117653 was used to study recombination between 4qA and 4qB alleles. A, Double digestion with PvuII/BlnI normally gives rise to fragments of 4,559 bp (chromosome 4 alleles) and 2,464 bp (chromosome 10 alleles). However, the presence of an extra PvuII site within the proximal D4Z4 unit yields a fragment of 2,849 bp. B, Example of the modified PvuII/BlnI dosage test after hybridization with probe p13E-11. Samples in lanes 1–3 carry two 4qA alleles and two 10q alleles, all of which are PvuII resistant (PvuII−). Samples in lanes 4–6 carry two 4qB alleles and two 10q alleles; in lane 4 and lane 6, a PvuII-sensitive (PvuII+) fragment is visible. “Y” indicates the cross-hybridizing Y chromosome. The table on the right shows dosage experiment results of the PvuII RFLP in the proximal D4Z4 unit of 78 different 4qA and 62 different 4qB alleles. Twenty-nine percent of the 4qB alleles are PvuII+, whereas 4qA alleles are almost exclusively PvuII− (P<10-5). C, Distribution of the PvuII RFLP on 4qA- and 4qB-type alleles. The PvuII− proximal D4Z4 unit on 4qA-type alleles is indicated by “−,” whereas D4Z4 units that were heterozygous for PvuII RFLP are indicated by “+/−.”