Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-08T05:34:10.393Z Has data issue: false hasContentIssue false
  • English
  • Français

Are macronuclear subunits in Paramecium functionally diploid?*

Published online by Cambridge University Press:  14 April 2009

Dennis Nyberg
Dennis Nyberg
Affiliation:
Department of Zoology, Indiana University, Bloomington, Indiana 47401, U.S.A.
Rights & Permissions [Opens in a new window]

Summary

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The organization of the genetic material in the macronucleus of ciliates has been the subject of considerable controversy. Two of the four models of macronuclear structure predict assortment of the alternative phenotypes of heterozygotes during vegetative growth. Early studies of the phenotypic behaviour of heterozygotes after macronuclear regeneration (Sonneborn, 1947) had supported a diploid subunit model. The availability of quantitative predictions of the rate of assortment for the haploid and chromosomal models (Preer, this volume) and the existence of two alleles controlling a quantitative trait, copper tolerance, in Paramecium tetraurelia, has provided an opportunity to test these models. The median tolerance limits to copper of unselected sublines were measured as a function of age. There was no increase in the variance among sublines, as the haploid and chromosomal models predict. Quantitative evaluation shows that subdiploid models with a kinetic complexity of 860 or less are not compatible with the results. This experiment was not sensitive enough, however, to exclude subdiploid models if the kinetic complexity is 2000 or greater. Selection on heterozygotes also failed to provide evidence in favour of assortment. All the results are consistent with and support the diploid subunit model of the Paramecium macronucleus.

Type
Research Article
Information
Genetics Research , Volume 27 , Issue 2 , April 1976 , pp. 239 - 248
Copyright
Copyright © Cambridge University Press 1976

References

Allen, S. L. & Gibson, I. (1972). Genome amplification and gene expression in the ciliate macronucleus. Biochemical Genetics 6, 293–313.CrossRefGoogle ScholarPubMed
Allen, S. L. & Li, C. I. (1974). Nucleotide sequence divergence among DNA fractions of different syngens of Tetrahymena pyriformis. Biochemical Genetics 12, 213–233.CrossRefGoogle ScholarPubMed
Ammermann, D. (1971). Morphology and development of the macronuclei of the ciliates Stylonychia mytilus and Euplotes aediculatus. Chromosoma 33, 209–238.CrossRefGoogle ScholarPubMed
Ammermann, D., Steiubrück, G., von Berger, L. & Hennig, W. (1974). The development of the macronucleus in the ciliated protozoan Stylonychia mytilus. Chromosoma 45, 401–429.CrossRefGoogle ScholarPubMed
Borden, D., Miller, E. T., Nanney, D. L. & Whitt, G. S. (1973). The inheritance of enzyme variants for tyrosine aminotransferase, NADP-dependent malate dehydrogenase, NADP-dependent isocitrate dehydrogenase, and tetrazolium oxidase in Tetrahymena pyriformis, syngen 1. Genetics 74, 81–106.CrossRefGoogle ScholarPubMed
Borden, D., Miller, E. T., Whitt, G. S. & Nanney, D. L. (1976). Electrophoretic analysis of evolutionary relationships in Tetrahymena. Evolution (in the Press).Google Scholar
Bostock, C. J. & Prescott, D. M. (1972). Evidence of gene diminution during the formation of the macronucleus in the protozoan Stylonychia. Proceedings of the National Academy of Sciences, U.S.A. 69, 139–142.CrossRefGoogle ScholarPubMed
Doerder, F. P. (1973). Regulatory serotype mutations in Tetrahymena pyriformis, syngen 1. Genetics 74, 81–106.CrossRefGoogle ScholarPubMed
Fauré-Fremiet, E. (1953). L'hypothèse de la sénescence et les cycles de réorganization nucléaire chez Ciliés. Revive Suisse de Zoologie 60, 426–438.Google Scholar
Genermont, J. (1966). Recherches sur les modifications durables et sur le déterminisme génétique de certain caractères quantitatifs chez Paramecium aurelia. Thèse, Faculté des Sciences de L'Université de Paris. 65 pp.Google Scholar
Kimura, M. (1957). Some problems of stochastic processes in genetics. Annals of Mathematical Statistics 28, 882–901.CrossRefGoogle Scholar
Kloetzel, J. A. (1970). Compartmentalization of the developing macronucleus following conjugation in Stylonychia and Euplotes. Journal of Cell Biology 47, 395–407.CrossRefGoogle ScholarPubMed
McCoy, J. W. (1973). A temperature-sensitive mutant in Tetrahymena pyriformis, syngen 1. Genetics 74, 107–114.CrossRefGoogle ScholarPubMed
Nanney, D. L. (1964). Macronuclear differentiation and subnuclear assortment in ciliates. In Role of the Chromosomes in Development (ed. Locke, M.), pp. 253–273. New York: Academic Press.CrossRefGoogle Scholar
Nyberg, D. (1975). Genetic analysis of copper resistance in Paramecium aurelia syngen 4. Genetics 80, 463–473.CrossRefGoogle ScholarPubMed
Orias, E. & Flacks, M. (1975). Macronuclear genetics of Tetrahymena. I. Random distribution of macronuclear gene copies in T. pyriformis syngen 1. Genetics 79, 187–206.CrossRefGoogle Scholar
Preer, J. R. Jr (1976). Quantitative predictions of random segregation models of the ciliate macronucleus. Genetical Research 27, 227–238.CrossRefGoogle ScholarPubMed
Prescott, D. M., Bostock, C. J., Murti, K. G., Lauth, M. R. & Gamow, E. (1971). DNA of ciliated protozoa. I. Electron microscopic and sedimentation analyses of macronuclear and micronuclear DNA of Stylonychia mytilus. Chromosoma 34, 355–366.CrossRefGoogle Scholar
Schwartz, V. & Meister, H. (1975). Einige quantitative Daten zum Problem des Alterns bei Paramecium, Archiv für Protistenkunde 117, 85–109.Google Scholar
Soldo, A. T. & Godoy, G. A. (1972). The kinetic complexity of Paramecium macronuclear deoxyribonucleic acid. Journal of Protozoology 19, 673–678.CrossRefGoogle ScholarPubMed
Sonneborn, T. M. (1947). Recent advances in the genetics of Paramecium and Euplotes. Advances in Genetics 1, 263–358.CrossRefGoogle ScholarPubMed
Sonneborn, T. M. (1954). The relation of autogamy to senescence and rejuvenescence in Paramecium aurelia. Journal of Protozoology 1, 38–53.CrossRefGoogle Scholar
Sonneborn, T. M. (1963). Does preformed cell structure play an essential role in cell heredity? In The Nature of Biological Diversity (ed. Allen, J. M.), pp. 165–221. New York: McGraw-Hill.Google Scholar
Sonneborn, T. M. (1974). Paramecium aurelia. In Handbook of Genetics, vol. 2 (ed. King, R. C.), pp. 469–594. New York: Plenum Press.CrossRefGoogle Scholar
Wolfe, J. (1967). Structural aspects of amitosis: A light and electron microscope study of the isolated macronuclei of Paramecium aurelia and Tetrahymena pyriformis. Chromosoma 23, 59–79.CrossRefGoogle Scholar
Woodard, J., Kaneshiro, E. & Gorovsky, M. A. (1972). Cytochemical studies on the problem of macronuclear subnuclei in Tetrahymena. Genetics 70, 251–260.CrossRefGoogle ScholarPubMed