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Maintenance of heterozygosity at the mt locus after autogamy in Euplotes minuta (Ciliata Hypotrichida)*

Published online by Cambridge University Press:  14 April 2009

R. Nobili  and
P. Luporini
R. Nobili
Affiliation:
Istituto di Zoologia, Università di Pisa, Pisa, Italy
P. Luporini
Affiliation:
Istituto di Zoologia, Università di Pisa, Pisa, Italy
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The genetic consequences of autogamy have been analysed in the autogamous strain A-25 of E. minuta. During autogamy as well as during conjugation four pronuclei (two genetically identical pairs) are formed in each individual. In conjugating pairs, any two of the four pronuclei of the autogamous conjugant may participate in synkaryon formation. Consequently, an 8:13 segregation ratio of clonal and synclonal mating-type inheritance has been found to occur in the progeny obtained by crossing A-25 animals with non-autogamous animals. During autogamy, synkaryon formation appears to be brought about by a preferential karyogamy of genetically dissimilar nuclei more often than is expected on a random basis. Therefore, heterozygosity is usually maintained after autogamy in spite of the extreme inbreeding characteristics of this sexual process.

Type
Research Article
Information
Genetics Research , Volume 10 , Issue 1 , August 1967 , pp. 35 - 43
Copyright
Copyright © Cambridge University Press 1967

References

REFERENCES

Corliss, J. O. (1965). L'autogamie et la sénescence du cilié hymenostome Tetraymena rostrata (Kahl). Ann. Biol. 4, 49–69.Google Scholar
Heckmann, K. (1963). Paarungssystem und genabhängige Paarungstypdifferenzierung den hypotrichen Ciliaten Euplotes vannus O. F. Müller. Arch. Protistenk. 106, 393–421.Google Scholar
Heckmann, K. (1964). Experimentelle Untersuchungen an Euplotes crassus. I. Paarungssystem Konjugation und Determination der Paarungstypen. Z. VererbLehre, 95, 114–124.Google Scholar
Katashima, R. (1960). Correlations between nuclear behavior and the disposition of the nuclei in cytoplasm during conjugation of Euplotes patella. J. Sci. Hiroshima Univ. Ser.B, 18, 239–263.Google Scholar
Luporini, P. & Nobili, R.New mating types and the problem of one or more syngens in Euplotes minuta (Ciliata Hypotrichida). Atti Ass. genet, ital. (in press).Google Scholar
Nobili, R. (1966 a). Mating types and mating type inheritance in Euplotes minuta Yocom (Ciliata Hypotrichida). J. Protozool. 13, 38–41.Google Scholar
Nobili, R. (1966 b). La riproduzione sessuale nei Ciliati. Boll. Zool. 32, 93–131.CrossRefGoogle Scholar
Siegel, R. W. & Heckmann, K. (1966). Inheritance of autogamy and the killer trait in Euplotes minuta. J. Protozool. 13, 34–38.Google Scholar
Sonneborn, T. M. (1947). Recent advances in the genetics of Paramecium and Euplotes. Adv. Genet. 1, 263–358.CrossRefGoogle ScholarPubMed
Sonneborn, T. M. (1957). Breeding systems, reproductive methods, and species problems in Protozoa. In ‘The species problems’ (Mayr, E., ed.). A.A.A. Sci. Symp. Wash., pp. 155–324.Google Scholar
Turner, J. P. (1930). Division and conjugation in Euplotes patella, Ehrbg. with special reference to the nuclear phenomena. Univ. Calif. Publs. Zool. 33, 193–258.Google Scholar
Wichterman, R. (1940). Cytogamy. A sexual process occurring in living joined pairs of Paramecium caudatum and its relation to other sexual phenomena. J. Morph. 66, 423–451.CrossRefGoogle Scholar