FERTILIZATION IN DROSOPHILA-MELANOGASTER - CENTROSOME INHERITANCE ANDORGANIZATION OF THE FIRST MITOTIC SPINDLE

Microtubule, chromatin, centrosome, and nuclear envelope configuration s during the first division of the Drosophila melanogaster zygote were analyzed in order to investigate the organization of the first cleava ge spindle and the origin of the functional centrosome. After pronucle ar apposition the parental complements congress at the equatorial plan e of the metaphase spindle. The chromatids, however, seem to move to t he poles in two separate groups in each half spindle, mingling togethe r during telophase, before the formation of the daughter nuclei. The s patial separation of parental complements during the first mitosis is also supported by the behavior of the nuclear envelope of female and m ale pronuclei. A low frequency of polyspermy is also observed during f ertilization in D. melanogaster. (C) 1996 Academic Press, Inc.