Homeo box gene expression in anterior and posterior regions of the Drosophila embryo.

The homeo box is a 180-base-pair coding sequence that has been implicated in the control of Drosophila development. A common feature of the nine previously reported homeo box genes is their involvement in the establishment of the segmentation pattern of the embryo. In this report we describe the isolation and properties of two additional homeo box genes, F90-2 and S67. Transcripts encoded by the two genes are detected in embryonic tissues that derive from regions near the anterior and posterior poles of the embryo, which are outside the limits of expression of known homeotic genes. These results suggest that at least some homeo box genes specify positional identity along the anterior-posterior body axis that is independent of the process of segmentation.