DDK egg-foreign sperm incompatibility in mice is not between the pronuclei.

A high rate of normal postimplantation development was achieved when the pronuclei of embryos from matings of DDK females with (CBA X C57BL/6J)F1 males were transplanted into enucleated embryos of non-DDK origin. This shows that the DDK egg cytoplasm, not the maternal pronucleus, is involved in the late preimplantation-lethal incompatibility.