Twinning, MonozygoticGenetic DeterminismCloning, OrganismCloning, MolecularClone CellsMammalsMolecular Sequence DataBase SequenceAmino Acid SequenceDNA, ComplementarySequence Homology, Amino AcidSequence Analysis, DNADNASequence Homology, Nucleic AcidRNA, MessengerPhylogenySequence AlignmentPolymerase Chain ReactionChromosome MappingNucleic Acid HybridizationEscherichia coliCell LineSpecies SpecificityGenesBlotting, SouthernGenes, BacterialPlasmidsBlotting, NorthernGene ExpressionRecombinant ProteinsDNA, BacterialDNA PrimersMutationDNA Restriction EnzymesGenomic LibraryTranscription, GeneticOpen Reading FramesTransfectionDNA, RecombinantChromosomes, Artificial, BacterialPhenotypeMultigene FamilyRestriction MappingCosmidsBiological EvolutionGene Expression RegulationGenetic VectorsGene LibraryEvolution, MolecularGenetic VariationTissue Distribution