Summary
We have isolated a bobbed (bb) mutant on the free duplication Dp(1; f)122bb + and we have measured the rDNA content of the bb + and the bb loci in genetic combinations in which none of the phenomena involved in the change of the rDNA redundancy occurs. We have also measured the rDNA content of the two bb loci carried by the free duplications in two different genetic combinations: (1) \(\widehat{{\text{XX}}}{\text{NO}}^ - /{\text{Dp}}122bb^ +\)and \(\widehat{{\text{XX}}}{\text{NO}}^ - /{\text{Dp}}122bb\)females in which there are two attached X chromosomes completely deleted for the nucleolus organizer (NO) regions and there-fore the only rDNA is contributed by the free duplication; (2) X/Dp122bb + and X/Dp122bb males, in which there are two bb loci, one on the X chromosome and the other on the X free duplication.
The bb + and the bb duplications produced an overall increase of the rDNA content in the two genetic conditions tested.
These results are not in favour of both a cis and trans effect of the regulator locus (cr + locus) hypothesised as being involved in the disproportionate replication of rRNA genes.
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Boncinelli E, Graziani F, Polito L, Malva C, Ritossa F (1972) rDNA magnification at the bobbed locus of the Y chromosome in Drosophila melalogaster. Cell Differ 1:133–142
Endow ES (1980) On ribosomal gene compensation in Drosophila. Cell 22:149–156
Endow ES, Glover DM (1979) Differential replication of ribosomal gene repeats in polytene nuclei of Drosophila. Cell 17:597–605
Gargano S, Graziani F (1976) Increase of rDNA redundancy in bb females of D. melanogaster. Mol Gen Genet 145:255–258
Gillespie D, Spiegelman S (1965) A quantiative assay for DNA-RNA hybrids with DNA immobilized on membrane. J Mol Biol 12:829–842
Henderson A, Ritossa F (1970) On the ineritance or rDNA of magnified bobbed loci in D. melanogaster. Genetics 66:463–473
Hennig W, Meer B (1971) Reduced polyteny of ribosomal RNA cistrons in giant chromosomes of D. hydei. Nature New Biol 233:70–72
Lindsley DL, Sandler L (1958) The meiotic behaviour of grossly deleted X chromosomes in Drosophila melanogaster. Genetics 43:547–563
Lindsley DL, Grell EH (1968) Genetic variation of D. melanogaster. Carnegie Inst of Washington, Publ no 627
Malva C, Gargiulo G, La Mantia G (1979) Different behaviour of Xbb + and Xbb chromosomes in D. melanogaster with only one nucleolar organizer. Mol Gen Genet 172:67–72
Marrakechi M, Prud'Homme N (1971) A study of bobbed mutants induced by ethil-methane-sulfonate in D. melanogaster. Biochem Biophys Res Commun 43:273–277
Mohan J, Ritossa F (1970) Regulation of rDNA synthesis and its bearing on the bobbed phenotype in D. melanogaster. Dev Biol 22:495–512
Procunier JD, Tartof KD (1978) A genetic locus having trans and contiguous cis functions that controls the disproportionate replication of rRNA genes in D. melanogaster. Genetics 88:67–79
Ritossa FM (1968) Unstable redundancy of genes for ribosomal RNA. Proc Natl Acad Sci USA 60:509–516
Ritossa FM, Atwood KC, Spiegelman S (1966) A molecular explanation of the bobbed mutants of Drosophila as partial deficiencies of ‘ribosomal’ DNA. Genetics 54:819–834
Ritossa FM, Malva C, Boncinelli E, Graziani F, Polito L (1971) The first steps of magnification of DNA complementary to ribosomal RNA in D. melanogaser. Proc Natl Acad Sci USA 68:1580–1584
Schalet A (1969) Exchanges at the bobbed locus of D. melanogaster. Genetics 63:133–153
Scherrer K, Darnell JE (1962) Sedimentation characteristics of rapidly labelled RNA from Hela cells. Biochem Biophys Res Commun 7:486–491
Shermoen AW, Kiefer BI (1975) Regulation of rDNA-deficient Drosophila melanogaster. Cell 4:275–280
Spear BB, Gall JG (1973) Indipendent control of ribosomal replication in polytene chromosome of D. melanogaster. Proc Natl Acad Sci USA 70:1359–1363
Tartof KD (1971) Increasing the multeplicity of ribosomal RNA genes in D. melanogaster. Science 171:294–297
Tartof KD (1973) Regulation of ribosomal gene multeplicity in D. melanogaster. Genetics 73:57–71
Weinmann R (1972) Regulation of ribosomal RNA and 5S RNA synthesis in D. melanogaster. Genetics 72:267–276
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Communicated by Ch. Auerbach
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La Volpe, A., La Mantia, G., Gargiulo, G. et al. Regulation of rRNA gene number in Drosophila melanogaster: New aspects resulting from the use of free duplications. Molec. Gen. Genet. 194, 485–488 (1984). https://doi.org/10.1007/BF00425562
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DOI: https://doi.org/10.1007/BF00425562