Chromosome Research

, Volume 3, Issue 7, pp 417–422

Stable chromosome fission associated with rDNA mobility



A spontaneous chromosome fission in the plantHypochoeris radicata has been characterized by Feulgen staining,in situ hybridization of the rDNA probe pTA71 and silver staining for active nucleolus organizing regions. The parental acrocentric chromosome has no detectable ribosomal genes at the centromere, but both fission derivatives possess active NORs at their centric ends. In fission heterozygotes, pachytene configurations studied by synaptonemal complex spreading show that the ribosomal cistrons form short arms on each telocentric which pair together to form a triradial. The paired short arms are associated with the single nucleolus at pachytene. It is proposed that the origin and stabilization of the fission rearrangement involved transposition of rDNA from the nucleolus organizing region of chromosome 3 into the centromeric region of chromosome 1.

Key words

chromosome fission NOR NOR movement rDNA 


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Copyright information

© Rapid Communications of Oxford Ltd 1995

Authors and Affiliations

  1. 1.the Department of Botany, School of Plant SciencesUniversity of Reading, WhiteknightsReadingUK

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