title: Evidence for position-effect suppression of the ribosomal RNA cistrons in Drosophila melanogaster.
abstract: Unambiguous evidence is presented that two X-chromosome inversions produce lethality in X/O males because of position-effect suppression of genes in the basal heterochromatin. The data support the hypothesis that the ribosomal RNA cistrons are the genes suppressed. There is evidence for a region in the X basal heterochromatin that may act as a regulator of rDNA activity.
mesh_terms: D000818:Animals; D002869:Chromosome Aberrations; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D004331:Drosophila melanogaster; D005260:Female; D005815:Genetic Code; D005838:Genotype; D006570:Heterochromatin; D008297:Male; D010641:Phenotype; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D011995:Recombination, Genetic; D012730:Sex Chromosomes
chemical_list: D006570:Heterochromatin; D012335:RNA, Ribosomal