Chromosome Research

, Volume 8, Issue 4, pp 313–317 | Cite as

Physical mapping, expression patterns and interphase organisation of rDNA loci in Portuguese endemic Silene cintrana and Silene rothmaleri

  • O. Pontes
  • H. Cotrim
  • S. Pais
  • W. Viegas
Article

Abstract

Double target in situ hybridization to root tip metaphase and interphase cells of Silene cintrana and Silene rothmaleri was used to allocate the position of 18S-5.8S-25S and 5S rRNA genes. In both species, the 18S-5.8S-25S rDNA probe labelled four sites located on the short arms of two submetacentric chromosomes. Only one locus for 5S rDNA was mapped adjacent to 18S-5.8S-25S genes in a subterminal position on the centromere side: in S. rothmaleri the 5S rDNA locus was adjacent to the small 18S-5.8S-25S locus while in S. cintrana it was near the large one. The NOR activity analysed by Ag-staining in metaphase cells revealed proportionality between in situ labelling dimensions and Ag-NORs. In both species all rDNA loci were potentially active, although in S. rothmaleri a tendency for the expression of only one locus was observed. Interphase organisation analysis of rDNA showed some differences between both species that were correlated with NOR activity.

Ag-NORs interphase rDNA organisation rDNA loci Silene cintrana Silene rothmaleri 

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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • O. Pontes
    • 1
  • H. Cotrim
    • 2
  • S. Pais
    • 2
  • W. Viegas
    • 1
  1. 1.Secção de Genética do Departamento de Botânica e Engenharia BiológicaInstituto Superior de AgronomiaLisboa CodexPortugal
  2. 2.ICAT, Edificio ICATCampus da Faculdade de Ciências da Universidade de LisboaLisboaPortugal

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