Lethal mutation rate in Drosophila treated with 20-methylcholanthrene.

Tumors in Drosophila are in many ways similar to atypical growths in mammals, although they are dissimilar in others (6). A frequent question concerning these tumors is whether carcinogens alter their incidence. This has been tested by treat ing a tumor stock of Drosophila with 20-methylcholanthrene and is reported at this time. In a previous study (4) it was shown that the lethal mutation rate is unchanged in the Oregon R stock after treatment with this carcinogen. Supplemen tary data on lethal mutation rate obtained in the present investigation are thought to have addi tional value, because tumor incidence was tabu lated at the same time.