Animals, Drosophila, Drosophila Proteins, Gene Expression Regulation, Developmental, Embryonic Development, Evolution, Molecular, Enhancer Elements, Genetic, Drosophila melanogaster, Transcription Factors, Computational Biology, Body Patterning, Oligonucleotide Array Sequence Analysis, Binding Sites, Nuclear Proteins, Phosphoproteins, Introns, Chromatin Immunoprecipitation, Phylogeny