title: Conservation of the expression of Dll, en, and wg in the eye-antennal imaginal disc of stalk-eyed flies.
abstract: We studied the developmental basis of exaggerated eye span in two species of stalk-eyed flies (Cyrtodiopsis dalmanni and Sphyracephala beccarn). These flies have eyes laterally displaced at the end of eyestalks, and males have greatly exaggerated eye span, which they use as a sexual display. To investigate eye span development we have compared eye-antennal disc morphology and the expression of three key regulator genes of Drosophila head development, Distal-less (Dll), engrailed (en), and wingless (wg), in the stalk-eyed flies and Drosophila. We found great similarity in the basic division of the disc into anterior-antennal and posterior-eye portions and in the general patterning of Dll, en, and wg. Unexpectedly, our results showed that although the eye and antenna are adjacent in adult stalk-eyed flies, their primordia are physically separated by the presence of an intervening region between the anterior and posterior portions of the disc. This region is absent from Drosophila eye-antennal discs. We chose two stalk-eyed fly species that differed in the degree of eye-stalk exaggeration but surprisingly we found no corresponding difference in the size of the en-wg expression domains that mark the boundaries of the dorsal head capsule primordia. In summary, our expression data establish the regional identity of the eye-antennal disc and provide a framework from which to address the developmental genetics of hypercephaly.
authors.affiliation: The Galton Laboratory, Department of Biology, University College London, UK.
authors.forename: I
authors.initials: I
authors.lastname: Hurley
authors.forename: K
authors.initials: K
authors.lastname: Fowler
authors.forename: A
authors.initials: A
authors.lastname: Pomiankowski
authors.forename: H
authors.initials: H
authors.lastname: Smith
mesh_terms: D000818:Animals; D004175:Diptera / Q000196:embryology / Q000235:genetics*; D029721:Drosophila Proteins; D015870:Gene Expression / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics*; D009928:Organ Specificity / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D051155:Wnt1 Protein
chemical_list: D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018398:Homeodomain Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051155:Wnt1 Protein; C117261:distal-less protein, insect; C074622:wg protein, Drosophila