title: Pulsed-field gradient-gel studies around the fragile site.
abstract: Using pulsed-field gradient-gel electrophoresis (PFGE) we compared two fragile X (fra(X] chromosomes from individuals in families that exhibit linkage heterogeneity between fra(X) and coagulation factor IX (F9). The analysis of very large restriction fragments indicated that there is a structural difference in the interval between fra(X) and F9 near the locus DXS105. Differences were observed in the Sfi I partial digestion analysis and in the Mlu I pattern of the DXS105 region. Digestion with Nru I and Sst II also showed differences between these alleles. The analyses suggest that the alleles differ in a region of greater than 200 kb. Analysis of other normal and fra(X) chromosomes will be necessary to determine whether the observed difference is a normal population variant or if it may be responsible for the linkage heterogeneity observed between these loci.
mesh_terms: D043283:Chromosome Fragile Sites; D002873:Chromosome Fragility; D002874:Chromosome Mapping; D004586:Electrophoresis; D005164:Factor IX / Q000235:genetics; D005600:Fragile X Syndrome / Q000235:genetics*; D008040:Genetic Linkage; D006801:Humans; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome
chemical_list: D005164:Factor IX