Radiosensitivity and chromosome numbers in strain L mouse cells in tissue culture.

The lethal effects of ionizing radiations on cells may be either genetic or nongenetic in origin and, if genetic, may be classified as dominant or recessive. If the radiosensitivity of an organism depends on its ploidy, it may be inferred that genetic damage is involved (1). Where such a dependence has been found, the relative importance of recessive and dominant lethal effects appears to account for the radiosensitivities observed (2, 3). Since it has been postulated that the loss of proliferative capacity by mammalian cells is principally the result of damage to chromosomes (4, 5), it is of interest to test for a ploidy effect in mammalian cells. An approach to this problem may be made by using strain L mouse cells in tissue culture, since a number of independently maintained cultures of this cell line have been found to differ considerably in chromosome number (6, 7). In this paper, the radiation survival curves for several selected L-cell lines differing in chromosome number are compared.