Published online by Cambridge University Press: 14 April 2009
A number of Hfr strains have been studied as to the action of radiations on the transmission of their genetic material to female cells. They form two classes, one in which irradiation produces only lesions that prevent transfer, and one in which new modes of chromosome transfer seem to be induced. One group of strains, derived from a common F+ male, appears to give rise to the same induced mode of transfer, while no correlation could be found in the other Hfr's studied.