9509101 RICE Genetic recombination is a prominent feature of virtually all complex, multicellular organisms. Yet some species of plants and animals lack this genetic feature, including many agriculturally important species like fruit trees, grape varieties, etc. The proposed research tests one of the prevailing theories about the importance of genetic recombination, i.e., it accelerates the rate of beneficial adaptation in response to environmental change. The common fruit fly (Drosophila melanogaster) is used as a model system owing to its inexpensive culturing, short generation time, and availability of numerous genetic tools critical for the operation of multi-generation experiments. Using a new strain recently developed in Dr. Rice's laboratory, he will experimentally vary the amount of genetic recombination in different populations. He will then challenge these populations with a new environment (low grade thermal stress), as it might occur during a period of rapid global warming. Next he will measure the rate of adaptation and relate this to the experimentally controlled level of genetic recombination. Current theory predicts that genetic recombination will greatly enhance the capacity of the populations to adapt to the new environment. The capacity for rapid adaptation is becoming increasingly important owing to the rapid environmental change induced by human activities. Results from these experiments will contribute to basic understanding of plant and animal breeding programs, and will help to predict the capacity of different life forms to adapt to human-induced environmental change.
