%0 Journal Article %A Larison, L. L. %A Siegel, R. W. %T Illegitimate Mating in Paramecium bursaria and the Basis for Cell Union %D 1961 %J Microbiology, %V 26 %N 3 %P 499-508 %@ 1465-2080 %R https://doi.org/10.1099/00221287-26-3-499 %I Microbiology Society, %X SUMMARY: Cells from stock Wu-67 of Paramecium bursaria, syngen 1, can be induced to conjugate inter se (self) if they have made brief but transitory contact with cells of a complementary mating type; in mixtures consisting of marked cells of Wu-67 and cells of a complementary mating type both interclonal and intraclonal (Wu-67 x Wu-67) conjugations were recognized. Unmixed cultures of Wu-67 never self nor could selfing be induced in other ways. In contrast to normal conjugation the intraclonal matings are illegitimate because they occur between cells expressing a common mating-type specificity. These and other facts are considered in light of Weiss's hypothesis about cell unions; it is postulated that a primary specific surface reaction dependent upon mating-type complementarity serves to elicit a secondary non-specific (‘holdfast’) reaction leading to the completion of conjugation. In cells from Wu-67 the sites of secondary reaction are held to be precociously or more readily activated than in normal cells and, when two such activated cells are apposed, illegitimate mating may occur. Under certain circumstances then, cellular adhesion and conjugation may be independent of primary mating-type complementarity and dependent instead upon the availability of secondary non-specific attachment sites. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-26-3-499