Meiosis success as indicated by the production of sexual progeny.

n =  number of conjugating (mating) pairs tested.
1 In Tetrahymena, conjugating cells produce sexual progeny by exchanging haploid meiotic products, whereupon both partners form zygotes. These mature into four genetically uniform karyonides which then begin vegetative multiplication by binary fission (e.g., [55], [56]). Success of meiosis was quantified by determining the percentage of conjugating pairs (matings) that produced viable sexual progeny.
2 If meiosis is faulty, matings may fail to produce progeny altogether or cells return to vegetative growth and produce clonal descendants. Thus viable descendants must be tested for their origin from successful meiosis. Clonal descendants possess the old somatic nucleus, which, in the parental strains, express a paromomycin resistance gene. Clonal descendants are therefore paromomycin-resistant. During sexual reproduction, the old somatic nuclei are degraded and new somatic nuclei lack the resistance gene, therefore sexual progeny are characterized by their paromomycin-sensitivity.
3rad51hp cells carry the RNAi hairpin construct but are not transcribing the hairpin RNA, whereas in rad51i cells hairpin transcription, and hence RNAi, is induced by treatment with CdCl2 (see Materials and methods).