title: Molecular and cytological characterization of a highly repeated DNA sequence in Raphanus sativus.
abstract: A highly repeated DNA sequence with a repeat unit of ca. 180 bp was found in genomic DNA HindIII-digests of Raphanus sativus. The repeating units of six isolated, independent clones were sequenced. These units have 177 or 178 bp, are 36% G+C in their DNA base composition, and show 90% sequence homology. The copy number of this 180-bp repeat unit is about 0.5 x 10(6) per diploid genome. In situ hybridization analysis with the repeating units as the probe and C-banding analysis indicated that the repeated DNA sequence of R. sativus is closely associated with the major C-heterochromatins in the proximal regions of all 18 chromosomes at mitotic metaphase.
authors.affiliation: Graduate Department of Gene Science, Faculty of Science, Hiroshima University, Higashi-Hiroshima, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hirai
authors.forename: K
authors.initials: K
authors.lastname: Irifune
authors.forename: R
authors.initials: R
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Morikawa
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D002871:Chromosome Banding; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics*; D006570:Heterochromatin; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014675:Vegetables / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D006570:Heterochromatin