GENETIC FEMINIZATION OF BRAIN STRUCTURES AND CHANGED SEXUAL ORIENTATION IN MALE DROSOPHILA

The neural basis of sexual orientation in Drosophila was studied by th e production of males with regionally feminized brains. Such flies exp ress the female form of the sex determination gene transformer in a li mited number oi neurons under the control of GAL4 enhancer trap insert s. This method facilitated the creation of lines with a stable pattern of feminization. In tests of sexual preferences, flies that were femi nized in a portion of the antennal lobes or in a subset of the corpora pedunculata (mushroom bodies) courted both males and females. These t wo brain structures, both of which are involved in olfactory processin g, may function in the recognition of sex-specific pheromones, in the control of sex-specific behaviors, or both.