Synaptic structures in the nuclei of sporulating yeast, Saccharomyces cerevisiae (hansen)

Abstract

After 4 h on sporulation medium the larger cells have formed, within the nucleolus, a spherical body of amorphous substance which stains less densely than the nucleolus. At 8 h most of these bodies contain synaptonemal complex-like structures. There is usually only one such body per nucleus. Only rarely are normal synaptonemal complexes detectable in the nucleus. At the first meiotic division these bodies are still present but they no longer have polycomplexes associated with them. At this time they become sequestered in a nuclear evagination and they are no longer detectable after the second meiotic division. It is argued that the polycomplex body may elaborate synaptic elements which function in meiotic chromosome pairing but that the resulting complexes are difficult to detect because of the lack of chromosome condensation, a characteristic of several fungi.