Site of action of imprinted genes revealed by phenotypic analysis of parthenogenetic embryos.

The phenotypes of early post-implantation parthenogenetic embryos were examined. The spectrum of phenotypes suggested that three stages are adversely affected by imprinting--implantation, pregastrulation, and postgastrulation. Survival of parthenogenetic embryos past these developmental blocks can be improved but not completely overcome by experimental asynchrony. These results suggest that imprinting may be "leaky" at early stages.