title: Characterization of a human 'midisatellite' sequence.
abstract: We have examined the structure and DNA sequence of a human genomic locus that consists of a large hypervariable region made up of repeats of a simple sequence. With several restriction enzymes, the locus shows many restriction fragments that vary quantitatively as well as qualitatively. Other restriction enzymes produce only a single, high-molecular-weight fragment at this locus. Almost all of the fragments are revealed with a simple sequence probe. Southern transfers of the high-molecular-weight restriction fragments produced by the restriction enzymes NotI and SfiI, resolved by pulsed-field gel electrophoresis, gave at most two fragments, demonstrated to be allelic, showing that the majority of the restriction fragments seen in the complex patterns are at a single locus. The estimated size of the region homologous to the probe varied from 250 to 500 kilobases. DNA sequencing indicated that the region consists of tandem repeats of a 40-base-pair sequence. Some homology was detected to the tandem repeating units of the insulin gene and the zetaglobin pseudogene hypervariable regions, and to the "minisatellite" DNA at the myoglobin locus.
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D003360:Cosmids; D004262:DNA Restriction Enzymes; D004276:DNA, Satellite / Q000235:genetics*; D005796:Genes; D014644:Genetic Variation; D006801:Humans; D007328:Insulin / Q000235:genetics; D008214:Lymphocytes; D009693:Nucleic Acid Hybridization; D011110:Polymorphism, Genetic
chemical_list: D004276:DNA, Satellite; D007328:Insulin; D004262:DNA Restriction Enzymes