INDEPENDENT SYNAPTIC BEHAVIOR OF SISTER CHROMATIDS IN COPRINUS-CINEREUS

Sister and nonsister chromatids behave in distinct ways during meiosis . We have shown that homologous synapsis does not require the presence of sister chromatids. In mutants that fail to undergo premeiotic DNA replication, synaptonemal complex of normal appearance is observed in diploid nuclei, but not in triploid nuclei. Our results indicate that homologous alignment does not depend on DNA replication. In addition, the differences observed in diploid and triploid nuclei indicate that sister chromatids can exhibit independent synaptic behavior, although ordinarily, they are constrained to act as a single unit.