GENETIC-CHARACTERIZATION OF 2 PHOTOTROPISM MUTANTS OF PHYCOMYCES WITHDEFECTS IN THE GENES MADL AND MADJ

Two Phycomyces genes, madI and madJ, which are involved in phototropis m, were characterized by recombination and complementation analyses. T he madI gene was located on linkage group IV of the genetic map of Phy comyces, 27 map units away from the gene carA. Complementation and rec ombination studies involving the genes madD, madE, madF, and madG, in combination with previous genetic studies, show that the recently isol ated mad-407 mutation defines a novel behavioural gene, madJ, of Phyco myces. A regulatory role of the madJ gene product in the light-sensory transduction pathway is suggested.