Dislocation of gold particles in the cytoplasm of mouse zygotes during cleavage

Abstract

Gold particles were introduced into mouse zygotes before the first cleavage. At cleavage, dislocation of particles within the cytoplasm was monitored. Cytoplasmic movement occurs in the central region of dividing zygotes as judged from the centripetal dislocation of particles there. Cytoplasm in polar regions appears less mobile. No particle crosses a vertical axis of the zygote during cytokinesis, which suggests that the cytoplasm of the arising blastomeres is not mixed. Our general conclusion is that the cytoplasmic territories of the mouse egg appear to be passively segregated between two blastomeres.