Nondisjunction, GeneticMeiosisCrossing Over, GeneticChromosomes, Human, Pair 21AneuploidyChromosome SegregationDown SyndromeTrisomyChromosomesSex ChromosomesRecombination, GeneticCentromereSpermatocytesChromatidsX ChromosomeMitosisOocytesAbnormalities, Radiation-InducedChromosomes, FungalSynaptonemal ComplexY ChromosomeCrosses, GeneticChromosome AberrationsSpores, FungalMaternal AgeDiploidyMetaphaseChromosome PairingChromosome MappingPotoroidaeTranslocation, GeneticSpermatogenesisSecale cerealeGenetic MarkersMutationIn Situ Hybridization, FluorescenceChromosomes, InsectMosaicismKaryotypingPaternal AgeMeiotic Prophase ISaccharomyces cerevisiaeNucleolus Organizer RegionGenetic TechniquesDrosophila melanogasterSex Chromosome AberrationsChromosome DisordersAnaphaseProphaseCell Cycle ProteinsSister Chromatid ExchangeSpindle Apparatusp-FluorophenylalanineChromosomes, PlantSpermatozoaPollenKinetochoresX-RaysPolyploidyChromosomal Proteins, Non-HistoneChromosomes, Human, Pair 18MutagensHeterozygoteChromosomes, Human, Pair 13Hygromycin BChromosome BreakagePachytene StageDrosophilaAllelesGenes, FungalSporesPhosphoribosylglycinamide FormyltransferaseChromosome BandingFungal ProteinsModels, GeneticZea maysOogenesisMonosomyPhenotypeSchizosaccharomyces pombe ProteinsHomozygoteDNA, FungalSchizosaccharomycesGenotypeHaploidyGenes, DominantMolecular Sequence DataGenes, RecessiveGerm Cells