OocytesOvumOogenesisOocyte DonationOocyte RetrievalXenopus laevisMeiosisIn Vitro Oocyte Maturation TechniquesXenopusMicroinjectionsFertilizationMetaphaseCumulus CellsParthenogenesisBlastocystSperm-Ovum InteractionsCryopreservationOvarySperm Injections, IntracytoplasmicEmbryonic DevelopmentEmbryo TransferZona PellucidaMaturation-Promoting FactorSpermatozoaZygoteCleavage Stage, OvumEmbryo Culture TechniquesRNA, ComplementaryPregnancyEgg ProteinsNuclear Transfer TechniquesFollicular FluidOvulation InductionCytoplasmProto-Oncogene Proteins c-mosCryoprotective Agents