Ribosomal RNA genes in B chromosomes of Crepis capillaris detected by non-radioactive in situ hybridization.
A non-radioactive in situ hybridization method using biotin-labelled rDNA has made it possible to localize rRNA genes not only at the secondary constriction in both homologous chromosomes No. 3 of Crepis capillaris but also in the B chromosomes occurring in the plants employed. Very clear dot-like rDNA signals at the telomeres of both arms were observed in all B chromosomes. Histochemical silver staining, which is indicative of transcriptional activity of rRNA gene clusters, resulted in both darkly-staining nucleolar constrictions of chromosomes No. 3 and silver deposits at the telomeres of Bs. We conclude that the B chromosomes of C. capillaris are isochromosomes with active rRNA genes located near both telomeres.
Maluszynska
J
J
Department of Cytology & Genetics, University of Vienna, Austria.
Schweizer
D
D
D002871:Chromosome Banding; D002875:Chromosomes / Q000648:ultrastructure*; D015342:DNA Probes; D005453:Fluorescence; D007399:Interphase; D008677:Metaphase; D009693:Nucleic Acid Hybridization; D009876:Operon; D010944:Plants / Q000235:genetics*; D012335:RNA, Ribosomal / Q000032:analysis; D012639:Seeds; D012407:rRNA Operon
D015342:DNA Probes; D012335:RNA, Ribosomal