Ian W. Duncan, Ph.D.

DEPARTMENT OF Genetics
Keywords: development, evolution, genetics, homeotic gene, ecdysone, Drosophila

Our research goal is to understand how genes specify the body segmentation pattern of Drosophila. We have identified the homeotic gene spineless (ss) as a key determinant of antennal segment identity. ss encodes a bHLH PAS protein that is a close relative of the mammalian dioxin receptor, a transcription factor that binds a wide variety of aryl hydrocarbon pollutants and activates genes encoding detoxification enzymes. Much of our work is concerned with determining how ss is regulated and how, in turn, ss regulates its own targets. We are also testing whether ss plays a conserved role in olfaction; the antenna is the major olfactory organ of the fly, and ss homologs are expressed within olfactory tissues in mammals and the nematode C. elegans.

We are also interested in how adult abdominal segments are patterned. The pigmentation pattern of abdominal segments is of particular interest, as this pattern is highly variable among even closely related species. We have identified several new genes involved in pigmentation in D. melanogaster, and these are now being tested to determine whether their homologs are responsible for variation in abdominal pigmentation in other species.

Finally, through our work on the abdomen we have become very interested in understanding why many genes switch their responsiveness to hedgehog, EGF and other signaling molecules in the early pupa. We find that this transition is controlled in part by the transcription factor E93, which is induced at the pupal stage by the molting hormone ecdysone.