Cytofluorimetric analysis of nuclear DNA during meiosis, fertilization and macronuclear development in the ciliate Tetrahymena pyriformis, syngen 1.

摘要: Fluorescence cytophotometry was used to study nuclear DNA content and synthesis patterns during meiosis, fertilization macronuclear development in the ciliated protozoon, Tetrahymena pyriformis, syngen 1. It found that cells entered conjugation with a G1 (45C) macronucleus G2 (4C) micronucleus. During meiosis micronucleus reduced 4 haploid nuclei, each 1C amount of DNA; meiotic product then replicated 2C, but only nucleus next attachment membrane conjugant divided form two gametic nuclei. The nuclei 2C prior fertilization; hence there no S-period 4C (synkaryon). first postzygotic division products immediately an become 4C, at second division, one Anlage. Anlagen began were about 8C completion conjugation; micronuclei did not undergo rapid doubling measured between 3C when conjugants separated. old participate any decompose after division; it contained average 24C end conjugation. From this sequence divisions pattern emerges that, unless general cytoplasmic signal for is suppressed, always occurs micronuclear following separation sister chromatids. Nuclear continued cell cycles In exconjugants (the cycle), underwent rounds 32C both also synthesis. However, completely disintegrated, remaining Anlage distributed resulting caryonide. At cycle, dividing caryonide 128C. These results relate question ploidy subunits. argued contains 22 or 23 diploid subunits, subunit being copy genome. suggested unequal relates by playing role phenomenon assortment.