title: Exclusive localization of tandem repetitive sequences in subtelomeric heterochromatin regions of Leymus racemosus (Poaceae, Triticeae).
abstract: Two kinds of tandem repetitive sequences were isolated from Leymus racemosus (Lam.) Tzvelev. One of them was classified in the 350-bp family originally isolated from Secale. The other was a novel repetitive sequence family, named 'TaiI family', which consisted of a repeat unit of 570 bp. Fluorescence in-situ hybridization of the chromosomes of L. racemosus indicated that both families were located in subtelomeric heterochromatin and that the 350-bp family and TaiI family occupied different heterochromatin regions. In addition, even homologous chromosomes did not show the same patterns of TaiI and 350-bp families. The combination of these two families of repetitive sequences, together with Afa-family sequences and rDNAs, helps to identify the ten homologous chromosome pairs of L. racemosus. From these data, we proposed a karyotype of L. racemosus and compared it with other karyotypes already reported.
authors.affiliation: Kihara Institute for Biological Research and Graduate School of Integrated Science, Yokohama City University, Yokohama, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kishii
authors.forename: K
authors.initials: K
authors.lastname: Nagaki
authors.forename: H
authors.initials: H
authors.lastname: Tsujimoto
authors.forename: T
authors.initials: T
authors.lastname: Sasakuma
mesh_terms: D001483:Base Sequence; D002874:Chromosome Mapping; D018744:DNA, Plant; D006570:Heterochromatin / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D006109:Poaceae / Q000235:genetics*; D020080:Tandem Repeat Sequences; D016615:Telomere
chemical_list: D018744:DNA, Plant; D006570:Heterochromatin