Coordination on timing of gene expression inParamecium

Abstract

In Paramecium caudatum, syngen 3, cells become mature (i.e. capable of undergoing conjugation) by about 50 fissions after conjugation. Matingtype-instability, another mating characteristic, begins to occur between 80 and 120 fissions after conjugation in heterozygotes for the mating type locus (Myohara & Hiwatashi, 1975). Mating-type instability also occurs in dominant homozygotes, earlier than in heterozygotes. In two different early maturing mutants the homozygotes become mature 20 fissions earlier than in wild-type clones, and mating-type instabiliiy also begins earlier than in wild-type clones. The number of fissions from maturity to the occurrence of the mating type change does not differ.

Stability in locomotive function of cilia according to clonal aging in <i>Paramecium</i>

“…The number of cell divisions after conjugation was estimated as previously described. 10) Approximately 800 cells were transferred into a new test tube containing 2 ml fresh culture medium. The next day, 4 ml of fresh culture medium was added to each tube, followed by 8 ml on each of the next 2 days.…”