PaleontologyFossilsVertebratesZebrafishMolecular Sequence DataGene Expression Regulation, DevelopmentalEvolution, MolecularChordata, NonvertebrateZebrafish ProteinsAmino Acid SequenceEmbryo, NonmammalianFishesBody PatterningBiological EvolutionLampreysHagfishesReptilesBase SequenceInvertebratesSequence Homology, Amino AcidIn Situ HybridizationXenopus ProteinsSequence AlignmentConserved SequenceSpecies SpecificityAmphibiansChordataHomeodomain ProteinsChickensCiona intestinalisSharksOryziasTakifuguGene Duplication