Summary
In Ascobolus immersus, 16 unstable mutants with white ascospores were isolated. These mutants mutate back to the wild-type phenotype with brown ascospores. Only two mutants B and 301 are the object of the present study. At least in these two mutants it was demonstrated that true back-mutations occur. The frequencies of back-mutations are quite high and can reach 0.30 in the case of mutant B.
The reversions appear at well defined but different for each mutant stages of the developmental cycle. These stages are relatively short and involve not more than about ten nuclear divisions cycles. In the case of mutant B, the back-mutations occur only in very young mycelia and at elevated temperature. Thus, the frequencies of back-mutations observed depend on the time of the transfer to higher temperature condition.
The back-mutations of 301 mutant occur only in spermatized female organ and depend on the genotype of the female parent.
The data established for Ascobolus immersus are compared with genic instability due to transposable elements described in corn by B. Mc Clintock.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bausum, H.T., Wagner, R.P.: “Selfing” and other form of aberrant recombination in isovaline mutants of Neurospora. Genetics 51, 815–830 (1965)
Decaris, B.: Etude génétique d'un mutant instable chez le champignon Ascobolus immersus. Thesis, University of Paris XI, Orsay (1973)
Decaris, B., Girard, J., Leblon, G.: Ascobolus, Handbook of genetics (R.C. King, ed.), Vol. 1, pp. 563–573, New York: Plenum Publishing Co. 1974
Decaris, B., Lefort, C., Rizet, G.: Etudes génétiques d'un mutant instable chez le champignon Ascobolus immersus. Société française de Génétique (1972)
Deshayes, A.: Mise en évidence d'une corrélation entre la fréquence de variations somatiques sur feuilles et l'état physiologique d'un mutant chlorophyllien monogénique chez Nicotiana tabacum. Mutation Res. 17, 323–323 (1973)
Fincham, J.R.S., Sastry, G.R.K.: Controlling elements in maize. An. Rev. Genet. 8, 15–50 (1974)
Francou, F.: Etude de l'instabilité d'un mutant à spores blanches chez le champignon Ascobolus immersus: influence de la température sur l'apparition et les modalités de réversion. Thesis, University of Paris XI, Orsay (1977)
Golubowsky, M.D., Ivanov, Y.N., Green, M.M.: Genetic instability in Drosophila melanogaster: putative multiple insertion mutants at the singed bristle locus. Proc. nat. Acad. Sci. (Wash.) 74, 2973–2975 (1977)
Green, M.M.: The genetics of a mutable gene at the white locus of Drosophila melanogaster. Genetics 56, 467–482 (1967)
Greenblatt, I.M.: The mechanism of modulator transposition in maize. Genetics 58, 585–597 (1968)
Guerdoux, J.-L.: Transformations spontanées du mutant nicotinique deux de Coprinus radiatus: étude de souches nic-2 homothalliques ou diploïdes. Molec. gen. Genet. 119, 119–129 (1972)
Harrisson, B.J., Fincham, J.R.S.: Instability at the Pal locus in Antirrhinum majus. I. Effects of environment on frequencies of somatic and germinal mutations. Heredity 19, 237–258 (1964)
Leblon, G.: Mechanism of gene conversion in Ascobolus immersus. I. Existence of a correlation between the origin of mutants induced by different mutagens and their conversion spectrum. Molec. gen. Genet. 115, 36–48 (1972)
Lewis, L.A., Decaris, B.: The induction of apothecial formation in Ascobolus immersus by a spermatization technique. Trans. Br. mycol. Soc. 63, 197–199 (1974)
Lieber, M.M.: The effects of temperature on genetic instability in Aspergillus nidulans. Mutation Res. 34, 93–122 (1976)
Lissouba, P., Mousseau, J., Rizet, G., Rossignol, J.-L.: Fine structure of genes in the ascomycete Ascobolus immersus. Adv. Genet. 11, 343–380 (1962)
MacClintock, B.: Controlling elements and the gene. Cold Spr. Harb. Symp. quant. Biol. 21, 197–216 (1956)
Mekki-Berrada, A., Rossignol, J.-L., Paquette, N.: Haute fréquence de réversion d'un mutant spontané chez Ascobolus immersus. C.R. Acad. Sci. (Paris) 283, 971–974 (1976)
Mitchell, H.K., Mitchell, M.B.: A case of maternal inheritance in Neurospora crassa. Proc. nat. Acad. Sci. (Wash.) 338, 442–445 (1952)
Mousseau, J.: On the possibility of carrying out the functional test for allelism in the ascomycete Ascobolus immersus. Proc. XI Int. Congr. Genet. 1, 36 (1963)
Nevers, P., Saedler, H.: Transposable genetic elements as agents of gene instability and chromosomal rearrangements. Nature (Lond.) 268, 109–115 (1977)
Nga, B.H., Ropper, J.A.: A system generating spontaneous intrachromosomal changes at mitosis in Aspergillus nidulans. Genet. Res. 14, 67–70 (1969)
Paquette, N.: Cartographie préliminaire des mutants morphologiques de la souche S2 d'Ascobolus immersus et mise en évidence d'un nouveau système génétique pour l'étude de la recombinaison intragénique avec marqueurs externes chez ce champignon. Mémoire — Université de Montréal (1972)
Paszewski, A., Surzycki, S.: “Selfers” and high mutation rate during meiosis in Ascobolus immersus. Nature (Lond.) 204, 809 (1964)
Paszewski, A., Surzycki, S., Mankowska, M.: Chromosome maps in Ascobolus immersus (Rizet's strain). Acta Soc. Bot. Pol. 35, 181–188 (1966)
Peterson, P.A.: The effect of temperature on the mutation rate of a mutable locus in maize. J. Hered. 49, 121–124 (1958)
Peterson, P.A.: Change in state following transposition of a regulatory element of the enhancer system in maize. Genetics 84, 469–483 (1976)
Rhoades, M.M.: The genetic control of mutability in maize. Cold Spr. Harb. Symp. quant. Biol. 9, 138–144 (1941)
Rizet, G.: Sur les spores dimorphes et l'hérédité de leurs caractères chez un nouvel Ascobolus hétérothallique. C.R. Acad. Sci. (Paris) 208, 1669 (1939)
Rizet, G., Engelman, C.: Contribution à l'étude génétique d'un ascomycète tétrasporé: Podospora anserina. Rev. Cyt. et Biol. Vég. 11, 201 (1949)
Rizet, G., Engelman, N., Lefort, C., Lissouba, P., Mousseau, J.: Sur un ascomycète intéressant pour l'étude de certains aspects du problème de la structure du gène. C.R. Acad. Sci. (Paris) 250, 2050–2052 (1960)
Rizet, G., Marcou, D., Schecroun, J.: Deux phénomènes d'hérédité cytoplasmique chez l'Ascomycète Podospora anserina. Bull. Soc. Fr. Physiol. Veg. 4 (no4), 136–149 (1958)
Rossignol, J.-L.: Phénomènes de recombinaison intragénique et unité fonctionnelle d'un locus chez l'Ascobolus immersus. Thesis, University of Paris XI, Orsay (1964)
Starlinger, P., Saedler, H.: Insertion mutations in microorganisms. Biochimie 54, 177–185 (1972)
Yu Sun, C.C.C.: Nutritional studies of Ascobolus immersus. Amer. J. Bot. 51, 231–237 (1964)
Yu Sun, C.C.C.: Linkage groups in Ascobolus immersus. Genetica 37, 569–580 (1966)
Zickler, D.: La méiose et les mitoses au cours du cycle de quelques Ascomycètes. Thesis, University of Paris XI, Orsay (1973)
Author information
Authors and Affiliations
Additional information
Communicated by W. Gajewski
Rights and permissions
About this article
Cite this article
Decaris, B., Francou, F., Lefort, C. et al. Unstable ascospore color mutants of Ascobolus immersus . Molec. Gen. Genet. 162, 69–81 (1978). https://doi.org/10.1007/BF00333852
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00333852