Abstract
UV induced adenine-requiring mutation in yeast cells was investigated quantitatively at several wavelengths of monochromatic UV and at maximum photoreversion conditions in the hope of elucidating the nature of mutagenesis. The results may be summarized as follows:
(1) In general, mutant production by UV and the remaining mutant, after subsequent treatment by VL at maximum photoreversion, both increased almost linearly against the UV dose, irrespective of the wavelengths used except for some deviation in the shorter wavelengths.
(2) Photoreversible and non-photoreversible fractions of the induced mutaion were determined by taking the ratios of the above two slopes.
(3) Using a scattering factor of UV at the cell boundary, reliable absolute cross sections of the mutation were obtained for the several wavelengths.
(4) Some implications of the above findings were discussed with special reference to the relation between mutation production and the inducible photochemical changes in DNA bases by UV.
