title: Nucleolus organizer and satellite association in a variant D-group chromosome.
abstract: A No. 15 chromosome with a short arm longer than usual is observed in two phenotypically normal brothers. This chromosome appears to have no visible satellite, shows no N-band staining, and is never involved in satellite association. These results have led us to the conclusion that this chromosome lacks the nucleolus organizer region.
mesh_terms: D002466:Cell Nucleolus; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000032:analysis; D002901:Chromosomes, Human, 13-15; D004247:DNA / Q000032:analysis*; D006570:Heterochromatin / Q000032:analysis; D006801:Humans; D008297:Male; D008938:Mitosis; D012335:RNA, Ribosomal / Q000096:biosynthesis
chemical_list: D006570:Heterochromatin; D012335:RNA, Ribosomal; D004247:DNA