ORGANIZATION OF THE HOX GENE-CLUSTER IN THE GRASSHOPPER, SCHISTOCERCA-GREGARIA

The conserved organization of the Hox genes throughout the animal king dom has become one of the major paradigms of evolutionary developmenta l biology. We have examined the organization of the Hox genes of the g rasshopper, Schistocerca gregaria. We find that the grasshopper Hox cl uster is over 700 kb long, and is not split into equivalents of the An tennapedia complex and the bithorax complex of Drosophila melanogaster . SgDax and probably also Sgzen, the grasshopper homologues of fushi-t arazu (ftz) and Zerknullt (zen), respectively, are also in the cluster , showing that the non-homeotic Antp-class genes, ''accessory genes,'' are an ancient feature of insect Hox clusters.