Cell lineage evaluation in preimplantation mouse embryos by intracellular injection of IgG.

The cell lineage in preimplantation mouse embryos was studied by injecting rabbit IgG into zygotes or into a blastomere of early or late 2-cell, 3- or 4-cell stage embryos. The localization of the IgG was detected by the peroxidase-antiperoxidase method. It was found that starting from the late 2-cell stage, lineage could be followed up to the cell populations of the blastocyst, inner cell mass and trophectoderm.