In Vitro Oocyte Maturation TechniquesOocytesOogenesisEmbryo Culture TechniquesSpindle ApparatusMeiosisMetaphaseFertilizationCumulus CellsOocyte RetrievalFertilization in VitroXenopus laevisMuscle SpindlesOocyte DonationOvaryOvumXenopusOvarian FollicleMaturation-Promoting FactorMicroinjectionsEmbryo TransferEmbryonic DevelopmentSperm Injections, IntracytoplasmicBlastocystParthenogenesisCryopreservationOvulation InductionStarfishChorionic GonadotropinGenes, mosProto-Oncogene Proteins c-mos