GENETIC-BASIS OF TOLERANCE TO O-2 DEPRIVATION IN DROSOPHILA-MELANOGASTER

The ability to tolerate a low-O-2 environment varies widely among spec ies in the animal kingdom. Some animals, such as Drosophila melanogast er, can tolerate anoxia for prolonged periods without apparent tissue injury, To determine the genetic basis of the cellular responses to lo w O-2, we performed a genetic screen in Drosophila to identify loci th at are responsible for anoxia resistance. Four X-linked, anoxia-sensit ive mutants belonging to three complementation groups were isolated af ter screening more than 10,000 mutagenized flies. The identified reces sive and dominant mutations showed marked delay in recovery from O-2 d eprivation. In addition, electrophysiologic studies demonstrated that polysynaptic transmission in the central nervous system of the mutant flies was abnormally long during recovery from anoxia. These studies s how that anoxic tolerance can be genetically dissected.