title: Chromosomal rearrangements which affect the chromosomal integration of the ribosomal genes in Drosophila melanogaster.
abstract: Sucrose gradient analysis of DNA from detergent-pronase lysates of whole adult flies has been used to examine a variety of genotypes for the presence of ribosomal genes not integrated into the DNA of the chromosome. Such genes were found in females in which one X chromosome carries an inversion, having one of its breakpoints between the nucleolus organizer and the centromere. These inversions move the nucleolus organizer to the distal end of the X chromosome. Other inversions which do not move the nucleolus organizer, as well as a series of bobbed deficiencies, did not induce unintegrated genes. The same inversions which induce unintegrated genes in adults also produce them in the diploid brain and imaginal discs of larvae. On the other hand, in the polytene salivary glands, unintegrated genes were found in every genotype examined.
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations; D002875:Chromosomes; D004247:DNA / Q000032:analysis; D004331:Drosophila melanogaster / Q000032:analysis; D005260:Female; D005796:Genes; D005838:Genotype; D008297:Male; D012270:Ribosomes; D012730:Sex Chromosomes
chemical_list: D004247:DNA