Cell Interactions and Ooplasmic Determinants

Microscopic observations of egg cytoplasm suggests that it is not homogenous in appearance. The observable variations in the cytoplasmic regions of the egg are referred to as cytoplasmic localizations. The cytoplasmic localizations do not all the time reflect the presence of ooplasmic determinants but only help to identify specific regions of cytoplasm. As we have mentioned before ooplasmic determinants (intrinsic factors) are apportioned not equally to different blastomeres during cleavage. In other words, the initial determination of cell fate is controlled by the specific ooplasmic determinants that a blastomeres receives. The determination of both the future germ cells and somatic cells lineage is decided through ooplasmic determinants. The role of ooplasmic determinants in the determination of gem cell lineage in nematodes and somatic cell lineage in tunicates.