In Vitro Oocyte Maturation TechniquesOocytesOogenesisEmbryo Culture TechniquesKinetochoresMeiosisMetaphaseSpindle ApparatusChromosome SegregationFertilizationMad2 ProteinsMaturation-Promoting FactorCumulus CellsMicrotubulesGenes, mosMitosisXenopus laevisMicroinjectionsPolar BodiesChromosomesOvumMammalsSperm-Ovum InteractionsOvarian FollicleEmbryonic DevelopmentEgg ProteinsXenopusParthenogenesisCell Cycle ProteinsZona PellucidaOvaryOocyte DonationMeiotic Prophase IAnaphaseCentromereBlastocystOocyte Retrieval