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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

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