title: Positional information and the bithorax complex.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development*; D005796:Genes; D008957:Models, Genetic; D009024:Morphogenesis; D009154:Mutation; D010641:Phenotype; D013909:Thorax / Q000254:growth & development