Quantification of fertilization-induced gamete changes and sperm entry without egg activation in a teleost egg


A cytological study of fertilization in the teleost, Catostomus commersoni, was carried out in order to quantify gamete changes induced by sperm entry and normal egg activation. Maternal metaphase II spindle length changes, blastodisc diameter changes, and sperm metamorphosis were quantified and found to be associated with normal fertilization. At the beginning of sperm transformation to a pronucleus, an ooplasmic specialization was found at the egg cortex just above the fertilizing sperm cell. The gamete changes mentioned above did not occur under water-deprived conditions which allowed sperm entry but not egg activation or sperm-pronucleus transformation. These results indicate that egg activation is necessary for normal sperm-pronucleus metamorphosis. © 1981.

Publication Title

Developmental Biology