Preferential binding of imaginal disk cells to embryonic segments of Drosophila.

Cell recognition and selective adhesion may be important in pattern formation; such processes in Drosophila melanogaster could be responsible for the maintenance of segment boundaries1, the morphogenesis of metamorphosing imaginal disks2, and the paths of axon outgrowth during neurogenesis3. As cells from different imaginal disks of Drosophila are able to recognize and sort out from one another4,5, we decided to investigate whether these larval cells could recognize and bind to the epidermis of intact embryos. We report here that imaginal disk cells bind preferentially to the epidermis of the embryonic segments from which they are derived: thoracic disk cells to thoracic segments and genital disk cells to abdominal segments. Furthermore, thoracic disk cells recognize and bind, without preference, to all segments of the homoeotic mutant Df(3R)P9 (ref. 6). We conclude, therefore, that cells of the same segmental origin have similar recognition properties at different developmental stages.