Abstract
The locations of nucleolus organizer regions in the genomes of D. neohydei, D. eohydei and D. repleta were studied by in situ hybridization. All three species carry one nucleolus organizer in the X heterochromatin. The Y chromosomes of D. neohydei and D. eohydei carry two nucleolus organizers in terminal positions comparable to those of D. hydei. The Y chromosome of D. repleta appears also to carry two nucleolus organizer regions, but this is difficult to establish because of the small size of this chromosome. In situ hybridization of ribosomal RNA with salivary gland chromosomes revealed the presence of additional ribosomal DNA sequence clusters in autosomes 2, 3 and 4 of D. neohydei. They form no nucleolus in salivary glands nor are they associated with the nucleolus originating from the sex chromosomal nucleolus organizers. After in vitro pulse-labelling salivary glands with radioactive RNA precursors, no autoradiographic label is associated with the autosomal ribosomal RNA genes. Transcript in situ hybridization gives no label in these autosomal loci. We conclude therefore that the autosomal rDNA sequences are inactive in salivary glands. In situ hybridization with clones of a major part of the 28S intervening sequence (IVS) of D. hydei to polytene chromosomes of D. neohydei results in intense hybridization of the 28S IVS fragment to the autosomal ribosomal DNA sequences. It is therefore suspected that most if not all of the rDNA copies in the autosomes contain an IVS. The inactivity of these ribosomal genes might be the consequence of the presence of intervening sequences in the 28S gene. These observation supply additional evidence in favour of a transcriptional inactivity of ribosomal genes with an IVS in Drosophila. Additional loci with IVS sequences are found in different positions of the genome which do not hybridize with rDNA sequences without IVS.
Similar content being viewed by others
References
Barasacchi-Pilone, G., Nardi, I., Batistoni, R., Andronico, F., Becari, E.: Chromosome location of the genes for 28S, 18S and 5S ribosomal RNA in Triturus marmoratus (Amphibia, Urodela). Chromosoma (Berl.) 49, 135–153 (1974)
Beermann, W.: Cytologische Analyse eines Camptochironomus Artbastards. I. Kreuzungsergebnisse und die Evolution des Karyotyps. Chromosoma (Berl.) 7, 135–153 (1955)
Dawid, I.B., Lauth, M., Wellauer, P.K.: Repetitive DNA elements related to the ribosomal insertion of Drosophila melanogaster. In: Miami Winter Symposium: Mobilization and reassembly of Genetic Information. 1980
Dover, G.A., Brown, S., Coen, E., Dallas, J., Strachan, T., Trick, M.: The dynamics of genome evolution and species differentiation. In: Genome evolution (Dover, G.A., Flavell, R.B., eds.) New York, Acdemic Press, 1982
Endow, S.A., Glover, D.M.: Differential regulation of ribosomal gene repeats in polytene nuclei of Drosophila. Cell 17, 597–605 (1979)
Gerbi, S.A.: Localization and characterization of the ribosomal RNA cistrons in Sciara coprophila. J. Mol. Biol. 58, 499–511 (1971)
Hennig, I.: Vergleichende Untersuchungen am Genom von D. hydei, D. neohydei und D. pseudoneohydei unter besonderer Berücksichtigung des Lampenbürsten-Y-Chromosoms in der männlichen Keimbahn. Diplomarbeit Fachbereich Biologie der Universität Tübingen (1972)
Hennig, I.: Vergleichend-zytologische und -genetische Untersuchungen am Genom der Fruchtfliegen-Arten Drosophila hydei, neohydei und eohydei (Diptera: Drosophilidae). Ent. Germ 4, 211–223 (1978)
Hennig, I.: “Hybrid” X-Y translocation chromosomes. Chromosoma (Berl.) 86, 491–508 (1982)
Hennig, W.: Molecular hybridization of DNA and RNA in situ. Int. Rev. Cytol. 36, 1–44 (1973)
Hennig, W., Link, B., Leoncini, O.: The location of the nucleolus organizer regions in Drosophila hydei. Chromosoma (Berl.) 51, 57–63 (1975)
Hennig, W., Meer, B.: Reduced polyteny of ribosomal RNA cistrons in giant chromosomes of Drosophila hydei. Nature (Lond.) New Biol. 233, 70–72 (1971)
Hirschi, M.: Replication patterns in polytene chromosomes of Drosophila hydei, D. neohydei and their hybrids. Arch. Genet. 49/50, 97–112 (1976, 1977)
Lifschytz, E., Hareven, D.: Heterochromatin markers. Chromosoma (Berl.) 86, 429–455 (1982)
Meyer, G.F., Hennig, W.: The nucleolus in primary spermatocytes of Drosophila hydei. Chromosoma (Berl.) 46, 121–144 (1974)
Patterson, J.T., Stone, W.S.: Evolution in the genus Drosophila. New York: Macmillan 1952
Poels, C.L.M.: Mucopolysaccharide secretion from Drosophila salivary gland cells as a consequence of hormone induced gene activity. Cell Diff. 1, 63–78 (1972)
Pukkila, P.J.: Identification of the lampbrush chromosome loops which transcribe 5S ribosomal RNA in Notophthalmus (Trituras) viridescens. Chromosoma (Berl.) 53, 71–89 (1975)
Stuart, W.D., Bishop, J.G., Carson, H.C., Frank, M.B.: Location of the 18S/28S ribosomal RNA genes in two Hawaiian Drosophila species by monoclonal immunological identification of RNA.DNA hybrids in situ. Proc. Natl. Acad. Sci. (Wash.) 78, 3751–3754 (1981)
Tymowska, J., Kobel, H.R.: Karyotype analysis of Xenopus mulleri (Peters) and Xenopus laevis (Dandin), Pipidae. Cytogenetics 11, 270–278 (1972)
Vogt, P., Hennig, W., Siegmund, I.: Identification of transcribed cloned Y chromosomal DNA sequences. Proc. Natl. Acad. Sci. (Wash.) 72, 5132–5136 (1982)
Wasserman, M.: Cytological studies of the releta group of the genus Drosophila. IV. The hydei subgroup. Univ. Texas Publ. No. 6205, 73–83 (1962)
Zacharias, H., Hennig, W., Leoncini, O.: Microspectrophotometric comparison of the genome sizes of Drosophila hydei and some related species. Genetica (Den Haag) 58, 153–157 (1982)
Author information
Authors and Affiliations
Additional information
We like to dedicate this paper to the memory of Angelika Funk
Rights and permissions
About this article
Cite this article
Hennig, W., Vogt, P., Jacob, G. et al. Nucleolus organizer regions in Drosophila species of the repleta group. Chromosoma 87, 279–292 (1982). https://doi.org/10.1007/BF00327630
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00327630