An investigation of some problems concerning nucleolus organizers in salamanders
- 1 January 1977
- journal article
- research article
- Published by Springer Nature in Chromosoma
- Vol. 59 (4), 283-299
- https://doi.org/10.1007/bf00327970
Abstract
Observed differences in the sizes of lampbrush nucleolus organizers in Plethodon cinereus have been shown by in situ hybridization to reflect true molecular differences in the numbers of ribosomal cistrons located at these organizers. Likewise, from in situ hybridization experiments on lampbrush and spermatocyte chromosomes it has been shown that animals may be, and indeed usually are, heterozygous with respect to the numbers of ribosomal cistrons on each half of the nucleolus bivalent. Filter hybridizations carried out on 33 males from a New Jersey population and 20 males from a Connecticut population have shown a 7.5-fold range in the numbers of ribosomal cistrons per diploid cell in the New Jersey population, and a 2.5-fold range in the Connecticut population. In view of the general heterozygosity of nucleolus organizers in these animals, the actual range in nucleolus organizer sizes in the New Jersey population is estimated to be at least 15-fold.Keywords
This publication has 32 references indexed in Scilit:
- Lampbrush chromosomes from semi-albino crested newts,Triturus Cristatus Carnifex (Laurenti)Cellular and Molecular Life Sciences, 1972
- Reduction of ribosomal RNA synthesis and ribosomal RNA genes in a mutant of Xenopus laevis which organizes only a partial nucleolus: II. The number of ribosomal RNA genes in animals of different nucleolar typesJournal of Molecular Biology, 1970
- Composition and structure of chromosomal and amplified ribosomal DNA's of Xenopus laevisJournal of Molecular Biology, 1970
- A low-viscosity epoxy resin embedding medium for electron microscopyJournal of Ultrastructure Research, 1969
- Properties and Composition of the Isolated Ribosomal DNA Satellite of Xenopus laevisNature, 1968
- Gene linkage by RNA-DNA hybridizationJournal of Molecular Biology, 1968
- A quantitative assay for DNA-RNA hybrids with DNA immobilized on a membraneJournal of Molecular Biology, 1965
- The association of satellited chromosomes with specific chromosomal regions in cultured human somatic cellsAnnals of Human Genetics, 1963
- The origin of spontaneous heteroploids in the progeny of diploid, triploid, and tetraploid axolotl femalesJournal of Experimental Zoology, 1959
- Lampbrush chromosomes from oocyte nuclei of the newtJournal of Morphology, 1954