Adaptations are central to the study of evolution. Thus it is surprising that we know so little about the molecular basis of adaptive evolution. The goal of my research is to identify, clone, and characterize the evolution of genes underlying natural adaptations in order to determine the types of genes involved, how many and what types of genetic changes occurred, and the evolutionary history of these changes. These data will address key questions. For example, do adaptations involve many genetic changes or only a few? How important are regulatory versu! s amino acid changes in adaptation? How often are “new” gene s involved in adaptations? Are most adaptive alleles new mutations or pre-existing alleles segregating at low to moderate frequency within a species? Clearly, a deeper understanding of how genes change during adaptation will give insight into the potential and limits of adaptive evolution.