title: Restriction analysis of chromosomal sequences homologous to single-copy fragments cloned from small polydisperse circular DNA (spcDNA).
abstract: Restriction fragments from the fraction of small polydisperse circular DNA (spcDNA) were cloned in pBR322. The spcDNA was prepared from cell cultures derived from an angiofibroma of a patient with tuberous sclerosis (TS). Such cultures have been shown previously to contain increased amounts of spcDNA. Four cloned spcDNA fragments containing single-copy sequences were chosen to characterize the homologous chromosomal DNA segments by restriction analysis. When used as hybridization probes, these four fragments generate well-defined nonvariable patterns in the chromosomal DNA from healthy donors. The restriction patterns obtained with one of the fragments (D-C4) can best be interpreted by assuming the presence of two copies of the homologous sequences in chromosomal DNA. A second sequence, A-B4, occurs at least 30-50 times in the haploid human genome. In both cases the duplicated regions span relatively large segments of DNA.
authors.affiliation: Abteilung Humangenetik der Universität, Ulm, Federal Republic of Germany.
authors.forename: G
authors.initials: G
authors.lastname: Assum
authors.forename: B
authors.initials: B
authors.lastname: Böckle
authors.forename: T
authors.initials: T
authors.lastname: Fink
authors.forename: U
authors.initials: U
authors.lastname: Dmochewitz
authors.forename: W
authors.initials: W
authors.lastname: Krone
mesh_terms: D001483:Base Sequence; D004270:DNA, Circular / Q000235:genetics*; D006801:Humans; D009693:Nucleic Acid Hybridization; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004270:DNA, Circular