Abstract
In the present study, somatic metaphase chromosomes of the millipede Enologus oxypygum (Diplopoda: Julida) were hybridized in situ with a sea urchin (Echinodermata) ribosomal probe (prRl4) in order to map major RNA genes (rDNA). Chromosomal preparations were also silver stained (Ag-NOR) to evaluate the rDNA transcriptional activity. Our results indicate that RNA genes are throughout heterochromatin in eight chromosomes involving 1/4 of the total heterochromatin which, in this species, is about 67% of the total DNA. Ag-NOR and FISH patterns were not coincident.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barzotti, R., F. Pelliccia & A. Rocchi, 1996. Heterochromatin and ribosomal genes in Asellus aquaticus (Crust. Isop.). Chrom. Res. 4: 177–181.
Cantone, M., R. Barbieri, G. Duro, V. Izzo & G. Giudice, 1993. Sequence analysis of the rDNA spacer of Paracentrotus lividus and observations about pre-DNA processing. Mol. Biol. 18: 177–182.
Colomba, M.S., R. Vitturi & M. Zunino, 2000. Karyotype analysis, banding, and fluorescent in situ hybridization in the scarab beetle Gymnopleurus sturmi McLeay (Coleoptera Scarabaeoeidea: Scarabaeidae). J. Hered. 91(3): 260–264.
Fitch, D.H.A., L.D. Strausbaugh & V. Barret, 1990. On the origins of tandemly repeated genes: Does hystone gene copy number in Drosophila reflect chromosomal location? Chromosoma 99: 118–124.
Howell, W.M. & DA. Black, 1980. Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method. Experientia 36: 1014.
Leitch, L.J. & J.S. Heslop-Harrison, 1992. Physical mapping of the 18S-5.8S-26S rRNA genes in barley by in situ hybridization. Genome 35: 1013–1018.
Libertini, A., M.S. Colomba & R. Vitturi, 2000. Cytogenetics of the amphipod Jassa marmorata Holmes, 1903 (Corophioidea: Ischyroceridae): karyotype, morphology, chromosome banding, fluorescent in situ hybridization and nuclear DNA content. J. Crust. Biol. 20 (2): 142–147.
Long, E.O. & I.D. Dawid, 1980. Repeated genes in eukaryotes, Ann. Rev. Biochem. 49: 727–764.
López-León, M.D., J. Cabrero & J.P.M. Camacho, 1999. Unusually high amount of inactive ribosomal DNA in the grasshopper Stauroderus scalaris. Chrom. Res. 7: 83–88.
Mandrioli, M., G.C. Manicardi, D. Bizzaro & U. Bianchi, 1999. NORs heteromorphism within a parthenogenetic lineage of the aphid Megoura viciae. Chrom. Res. 7: 157–162.
Pendás, A.M., P. Morán & E. Garcia-Vázquez, 1993. Ribosomal RNA genes are interspersed throughout a heterochromatic chromosome arm in Atlantic salmon. Cytogenet. Cell Genet. 63: 128–130.
Sumner, A.T., 1972. A simple technique for demonstrating centromeric heterochromatin. Exp. Cell Res. 75: 304–306.
Vitturi, R., M.S. Colomba, R. Barbieri & M. Zunino, 1999. Ribosomal DNA location in the scarab beetle Thorectes intermedius (Costa) (Coleoptera: Geotrupidae) using banding and fluorescent in situ hybridization. Chrom-Res. 7: 1–6.
Vitturi, R., M.S. Colomba, V. Caputo, I. Sparacio & R. Barbieri, 1997. High heterochromatin content in somatic chromosomes of two unrelated species of Diplopoda (Myriapoda). Chrom. Res. 5: 407–412.
Wachtler, F., A.H. Hopman, J. Wiegant & H.G. Schwarzacher, 1986. On the position of nucleolus organizer regions (NORs) in interphase nuclei. Studies with a new non-autoradiographic in situ hybridization method. Exp. Cell Res. 167: 227–240.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Vitturi, R., Colomba, M., Mandrioli, M. et al. 18S-28S rDNA is interspersed throughout heterochromatin in the millepede Enologus oxypygum (Diplopoda). Genetica 110, 151–155 (2000). https://doi.org/10.1023/A:1017928826304
Issue Date:
DOI: https://doi.org/10.1023/A:1017928826304