title: Non-random loss of uninterrupted ribosomal DNA repeating units upon induction of a bobbed mutation.
abstract: To investigate the physical organization of ribosomal RNA genes of two bobbed (bb) loci carried by the Dp(1;f)122 free duplication, a wild type and a deleted one derived from it, genomic DNAs from XXNO-/Dp122bb+ and XXNO-/Dp122bb adult females were analyzed by restriction enzyme digestions. We found that in the bb mutant there was a loss of uninterrupted genes, while genes interrupted by type I and type II insertions remained apparently unchanged. This is an indication that at least in this wild type bb+ locus, carried by the 122 free duplication, the different repeating units are not distributed randomly. In fact, after digestion of the rDNA carried by the bb+ duplication with the enzyme BamHI that cuts only in type I insertions, we have obtained long uncleaved fragments of DNA containing uninterrupted genes.
mesh_terms: D000818:Animals; D001345:Autoradiography; D004247:DNA / Q000235:genetics*; D004262:DNA Restriction Enzymes; D004275:DNA, Ribosomal; D004331:Drosophila melanogaster; D005260:Female; D009154:Mutation; D009693:Nucleic Acid Hybridization; D012335:RNA, Ribosomal / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D012270:Ribosomes
chemical_list: D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D004247:DNA; D004262:DNA Restriction Enzymes