This award will support collaborative research between Dr. Richard Halliburton of Western Connecticut State University and Professor James S.F. Barker of the University of New England, New South Wales, Australia. The principle objectives are to survey Australian populations of Drosophila species for variation and differentiation of mitochondrial DNA, as detected by enzyme analysis, and to estimate correla- tions with genetic variability and with environmental variables. Mitochondrial DNA has become an effective tool for inferring evolutionary relationships. For one, because it does not undergo recombination, it alleviates problems associated with more conventional genetic analysis of evolutionary problems. Project results will advance understanding of the extent and nature of genetic variation in desert Drosophila, the nature of interactions between mitochondrial and chromosomal DNA, and enable comparisons between Drosophila species in the United States and Australia. The project represents excellent collaboration between the Australian researcher, world-known for his studies of the evolutionary genetics of Drosophila and Halliburton's expertise in enzyme studies that suggest that genetic variability is maintained by balancing natural selection, and not by migration or genetic drift. Validation of the Halliburton hypothesis would be strongly enhanced by testing over the wide geographical range offered by the Australian cooperation. Comparisons of desert Drosophila in the United States and Australia will advance basic understanding of the nature and causes of genetic variation in desert Drosophila. In addition, the research has potential to further under- standing of the evolution of desert organisms in general, with potentially important ecological implications.
