RESEARCH PROPOSAL Scientific Merit: Dr. Jockusch is interested in taking advantage of comparative developmental analysis of insects to investigate evolution of gene regulatory networks. By comparing regulatory genes that function in development in a variety of insects she hopes to glean some insights into the nature of the changes underlying the origin of the insect wing and changes affecting position and number of legs. The information obtained in this specific analysis is expected to illustrate general features of the evolution of developmental systems. Her first project will be to explore the origin of wings by (partially) cloning non-dipteran homologues of three genes (snail, escargot, apterous) known to be important in wing development in Drosophila. Technically this project seems reasonable and she has proposed alternative approaches should her primary method be unsuccessful. She will used these clones to determine the patterns of expression in four insects, Drosophila, Schistocerca, Thermobia and a member of the Archeognatha, perhaps Petrobius. She will use these data to help discriminate between competing hypotheses for the origin of wings. To her credit she has considered possible outcomes and how they might be interpreted. Also as part of this project she will attempt to perform some cell lineage tracing. These tracing experiments will permit her to follow the migration of cells and determine the origin of primordial wing cells which will, again, help her distinguish between competing hypotheses for the origin of wings. The power of this type of an approach was recently seen in the article by Averof and Cohen (Nature 385:327) who also addressed the question of the origin of wings and used apterous expression as a marker. They compared expression in a crustacean and Drosophila and weighed in on the wings from legs camp. Dr. Jockusch's approach will be very similar but her choice of organisms is somewhat different and consequently her data will be unique and relevant to these interesting questions. Her second project is concerned with leg development and specifically the evolutionary loss of abdominal legs. A key reason why flies lack abdominal appendages but crustaceans do not is a difference in the ability of abd-A to repress Dll in flies but not in crustacea. Dr. Jockusch is proposing to determine whether this change in the regulatory ability of abd-A occurred simultaneously with the loss of abdominal limbs. She will therefore determine if abd-A and Dll are coexpressed in insect possessing abdominal appendages (Thysanura and Archeognatha) and in those lacking abdominal legs (Schistocera). Antibodies are available although she is prepared to clone these genes if necessary. Again, she considers possible outcomes and how they will influence her interpretation. Overall the scientific merit of this proposal is outstanding.
