Stable chromosome fission associated with rDNA mobility.
A spontaneous chromosome fission in the plant Hypochoeris 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.
Department of Botany, School of Plant Sciences, University of Reading, Whiteknights, UK.
K J
KJ
Hall
J S
JS
Parker
D002869:Chromosome Aberrations / Q000235:genetics*; D004396:Coloring Agents; D015342:DNA Probes; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D017403:In Situ Hybridization; D008854:Microscopy, Electron; D009697:Nucleolus Organizer Region / Q000235:genetics* / Q000378:metabolism; D010944:Plants / Q000235:genetics*; D012394:Rosaniline Dyes; D016622:Silver Staining; D013573:Synaptonemal Complex / Q000235:genetics; D016615:Telomere / Q000235:genetics
D004396:Coloring Agents; D015342:DNA Probes; D004275:DNA, Ribosomal; C007722:Feulgen stain; D012394:Rosaniline Dyes