Abstract
Intraspecific variability of rDNA content in two cultivars of Allium cepa and in a strain of Allium sativum (U type) was studied by filter hybridization of 3H-rRNA with DNA extracted from roots of individual bulbs. The range of variation in% hybrid values was 2-fold (0.052% to 0.106%) and 2.5-fold (0.049% to 0.124%) in the two Allium cepa cultivars, but it was much smaller (0.048% to 0.061%) in the Allium sativum strain. — In both Allium cepa cultivars studied plants were observed carrying two, three or four nucleolus organizers per cell; cytological polymorphism of the nucleolus organizer regions was demonstrated by Giemsa C-banding. The number of ribosomal cistrons per genome of the bulb does not seem to be strictly dependent upon the number of nucleolus organizers per cell, and no relationship was detected between Giemsa banding pattern of nucleolar chromosomes and rDNA content of the bulb.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Avanzi, S., Durante, M., Cionini, P.G., D'Amato, F.: Cytological localization of ribosomal cistrons in polytene chromosomes of Phaseolus coccineus. Chromosoma (Berl.) 39, 191–204 (1972)
Avanzi, S., Maggini, F., Innocenti, A.M.: Amplification of ribosomal cistrons during the maturation of metaxylem in the root of Allium cepa. Protoplasma (Wien) 76, 197–210 (1973)
Battaglia, E.: Allium ascalonicum, A. fistolosum, A. cepa. Analisi cariotipica. Caryologia (Firenze) 10, 1–28 (1957)
Battaglia, E., Maggini, F.: The use of osmium for staining the nucleolus in squash technique. Caryologia (Firenze) 21, 287–292 (1968)
Bougourd, S.M., Parker, J.S.: Nucleolar-organizer polymorphism in natural populations of Allium schoenoprasum. Chromosoma (Berl.) 56, 301–307 (1976)
Callan, H.G.: Chromosomes and nucleoli of the axolotl. Ambystoma mexicanum. J. Cell Sci. 1, 85–108 (1966)
Cullis, C.A.: Ribosomal RNA cistrons number in Nicotiana species and derived haploids. Chromosoma (Berl.) 50, 435–441 (1975)
Cullis, C.A., Davies, D.R.: Ribosomal DNA amounts in Pisum sativum. Genetics 81, 485–492 (1975)
Doerschug, E.B.: Placement of the genes for ribosomal RNA within the nucleolar organizing body of Zea mays. Chromosoma (Berl.) 55, 43–56 (1976)
Durante, M., Cremonini, R., Brunori, A., Avanzi, S., Innocenti, A.M.: Differentiation of metaxylem cell line in the root of Allium cepa: DNA heterogeneity and ribosomal RNA cistrons in cells of two different stages of differentiation. Protoplasma (Wien) 93, 289–303 (1977)
Funaki, K., Matsui, S., Sasaki, M.: Location of nucleolar organizer in animal and plant chromosomes by means of an improved N-banding technique. Chromosoma (Berl.) 49, 357–370 (1975)
Givens, J.F., Phillips, R.L.: The nucleolus organizer region of maize (Zea mays L.). Ribosomal RNA gene distribution and nucleolar interactions. Chromosoma (Berl.) 57, 103–117 (1976)
Hennen, S., Mizuno, S., Macgregor, H.C.: In situ hybridization of ribosomal DNA labelled with 125Iodine to metaphase and lampbrush chromosomes from newts. Chromosoma (Berl.) 50, 349–369 (1975)
Hutchinson, N., Pardue, M.L.: The mitotic chromosomes of Notophtalmus (=Triturus) viridescens: localization of C-banding regions and DNA sequences complementary to 18S, 28S and 5S ribosomal RNA. Chromosoma (Berl.) 53, 51–69 (1975)
Konvicka, O., Levan, A.: Chromosome studies in Allium sativum. Hereditas (Lund) 72, 129–148 (1972)
Lewontin, R.C.: The genetic basis of evolutionary changes. New York: Columbia University Press 1974
Macgregor, H.C.: The role of lampbrush chromosomes in the formation of nucleoli in amphibian oocytes. Quart. J. micr. Sci. 106, 215–228 (1965)
Macgregor, H.C., Kezer, J.: The chromosomal localization of a heavy satellite DNA in the testis of Plethodon c. cinereus. Chromosoma (Berl.) 33, 167–182 (1971)
Macgregor, H.C., Vlad, M., Barnett, L.: An investigation of some problems concerning nucleolus organizers in salamanders. Chromosoma (Berl.) 59, 283–299 (1977)
Maggini, F.: Homologies of ribosomal RNA nucleotide sequences in monocots. J. molec. Evol. 8, 317–322 (1975)
Maggini, F., Garbari, F.: Amount of ribosomal DNA in the subgenus Allium sect. Allium. Plant System. Evol. 128, 201–208 (1977)
Mandell, S.D., Herschy, A.D.: A fractionating column for analysis of nucleic acids. Anal. Biochem. 1, 66–77 (1960)
Miller, L., Brown, D.D.: Variation in the activity of nucleolar organizers and their ribosomal gene content. Chromosoma (Berl.) 28, 430–444 (1969)
Mohan, J., Flavell, R.B.: Ribosomal RNA cistron multiplicity and nucleolar organizers in hexaploid wheat. Genetics 76, 33–44 (1974)
Noda, S.: A new typed nucleolar chromosome and a supernumerary fragment chromosome in Allium cepa L. Mem. Fac. Science, Kyushu Univ., Ser. E. 1, 139–146 (1953)
Ramirez, S.A., Sinclair, J.H.: Intraspecific variation of ribosomal gene redundancy in Zea mays. Genetics 80, 495–504 (1975)
Ritossa, F.M., Scala, G.: Equilibrium variations in the redundancy of rDNA in Drosophila melanogaster. Genetics, Suppl. 1 61, 305–317 (1969)
Ritossa, F.M., Spiegelman, S.: Localization of DNA complementary to ribosomal RNA in the nucleolus organizing region of Drosophila melanogaster. Proc. nat. Acad. Sci. (Wash.) 53, 737–745 (1965)
Scheuermann, W., Knälmann, M.: Localization of ribosomal cistrons in metaphase chromosomes of Vicia faba L. Exp. Cell Res. 90, 463–465 (1975)
Schmidtke, J., Zenzes, M.T., Weiler, C., Bross, K., Engel, W.: Gene action in fish of tetraploid origin. IV. Ribosomal DNA amount in clupeoid and salmonoid fish. Biochem. Genet. 14, 293–297 (1976)
Siegel, A., Lighfoot, D., Ward, O.G., Keener, S.: DNA complementary to ribosomal RNA: relation between genomic proportion and ploidy. Science 179, 682–683 (1973)
Sinclair, J.H., Carroll, C.R., Humphrey, R.R.: Variation in rDNA redundancy level and nucleolar organizer length of the mexican axolotl. J. Cell Sci. 15, 239–257 (1974)
Spear, B.B., Gall, J.G.: Independent control of ribosomal gene replication in polytene chromosomes of D. melanogaster. Proc. nat. Acad. Sci. (Wash.) 70, 1359–1363 (1973)
Stack, J.M., Clarke, C.R.: Differential Giemsa staining of the telomeres of Allium cepa chromosomes: observations related to chromosome pairing. Canad. J. Genet. Cytol. 15, 619–624 (1973)
Timmis, J.N., Ingle, J.: Environmentally induced changes in rRNA gene redundancy. Nature (Lond.) New Biol. 244, 235–236 (1973)
Vosa, C.G.: Heterochromatin recognition and analysis of chromosome variation in Scilla sibirica. Chromosoma (Berl.) 43, 269–278 (1973)
Vosa, C.G.: Heterochromatic patterns in Allium. I. The relationship between the species of the cepa group and its allies. Heredity 36, 383–392 (1976)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Maggini, F., Barsanti, P. & Marazia, T. Individual variation of the nucleolus organizer regions in Allium cepa and A. sativum . Chromosoma 66, 173–183 (1978). https://doi.org/10.1007/BF00295138
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00295138