caa a22 4500 477089577 CHVBK 20180405111512.0 cr unu---uuuuu 170330e19961101xx s 000 0 eng 10.1007/BF02261779 doi (NATIONALLICENCE)springer-10.1007/BF02261779 Molecular diversification of tandemly organized DNA sequences and heterochromatic chromosome regions in some triticeae species [Elektronische Daten] [A. Vershinin, E. Alkhimova, J. Heslop-Harrison] The subtelomeric heterochromatin of rye (Secale cereale) chromosomes makes up 12-18% of the genome and consists largely of a small number of tandemly organized DNA sequence families. The genomic organization, chromosomal locations and the structural organization of monomer units of the major DNA sequences from these regions were investigated and compared in other Triticeae species from the generaSecale, Agropyron, Dasypyrum, Triticum andHordeum. Southern hybridization and polymerase chain reaction analysis established that all studied species preserve the tandem type of sequence organization but the copy number is altered drastically between species. In the pSc200 family, a fraction of the tandem arrays is present with a head-to-head orientation of dimers inS. cereale andS. montanum. Members of the same family are more heterogeneous and present as head-to-head monomers in theDasypyrum species andA. cristatum. In situ hybridization demonstrates different organization of the sequence families in the various species: pSc200 and pSc250 are concentrated in major blocks at the ends of most rye chromosome arms, whereas they are more dispersed and in smaller blocks inDasypyrum andAgropyron indicating that accumulation is not simply due to the sequence itself. In contrast to rye,D. villosum has large blocks of only pSc200 whereasD. breviaristatum shows greater amplification of pSc250. These data indicate that each repetitive family is an independent unit of evolution, and suggest that the twoDasypyrum species are not closely related. The data are discussed in terms of existing evolutionary models for repetitive DNA sequences. The contribution of random events, through molecular drive and selection, to the evolution of heterochromatic regions is considered. Rapid Science Publishers, 1996 genome organization nationallicence molecular evolution nationallicence rye nationallicence Secale cereale nationallicence tandem repeats nationallicence Vershinin A. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut Alkhimova E. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut Heslop-Harrison J. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut Chromosome Research Kluwer Academic Publishers 4/7(1996-11-01), 517-525 0967-3849 4:7<517 1996 4 10577 https://doi.org/10.1007/BF02261779 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02261779 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Vershinin A. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut NATIONALLICENCE 700 1- Alkhimova E. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut NATIONALLICENCE 700 1- Heslop-Harrison J. Karyobiology Group, Department of Cell Biology, John Innes Centre, NR4 7UH, Norwich, UK aut NATIONALLICENCE 773 0- Chromosome Research Kluwer Academic Publishers 4/7(1996-11-01), 517-525 0967-3849 4:7<517 1996 4 10577 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer