Regulation of Expression of the Hox 2.3 Gene

Only few vertebrate genes have been described, that can be unambiguously linked to developmental processes. For this reason, investigators of vertebrate embryology concentrate their attention on genes for which the evidence implicating them in pattern formation is only circumstantial. The homeobox containing genes (1), found throughout the animal kingdom including mice and humans, exemplify such genes. In the genetically well-characterized fruitfly Drosophila melanogaster their involvement in various stages of the segmentation of the embryo and in neuronal development (1, 2) is beyond doubt, although their precise function still has to be established.