Indispensable function of the germ nucleus for postconjugational stomatogenesis inParamecium caudatum: Evidence against its genic function shown by hypohaploid micronuclei
✍ Scribed by Nakajima, Yuka ;Mikami, Kazuyuki
- Book ID
- 101297669
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 188 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0192-253X
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✦ Synopsis
It is known that the germinal micronucleus at the stages of gametogenesis and/or fertilization has an indispensable function for the postconjugational development of oral apparatus (stomatogenesis) in Paramecium caudatum. To determine whether this function is due to some specific genes in the micronucleus, postconjugational stomatogenesis was examined in the conjugation of haploid and hypohaploid cells. Haploid clones were obtained by conjugation between amicronucleate cells and diploid micronucleate cells. After conjugation between these haploid clones or between the haploid clones and amicronucleate clones, we succeeded in obtaining hypohaploid clones that have various types of nullisomic micronuclei. If a few genes in the micronucleus control postconjugational stomatogenesis, some hypohaploid micronuclei should undergo stomatogenesis normally, but others should not. In the present work, however, almost all the hypohaploid micronuclei developed the oral apparatus and formed food vacuoles. We can apparently rule out the possibility that a few specific genes of the micronucleus are required for postconjugational stomatogenesis in Paramecium caudatum, unless selection operates to retain the chromosomes with the essential gene(s). Dev. Genet.