Formation and rejoining of DNA strand breaks in x (γ)-irradiated cells in relation to the structure of mammalian chromatic

Mammalian cells usually possess the capacity to rejoin disruptions introduced into their deoxynucleoprotein structures by ionizing radiation. I believe that analyses of the strand-break-inducing and the strand-break-rejoining mechanisms operating on the DNA of irradiated cells can provide clues to the nature of the structure of mammalian chromatin in situ. In particular, I wish to consider evidence relevant to the idea that mammalian DNA contains special sites which are sensitive to radiation, alkali, and perhaps other agents and treatments. This concept is usually referred to as the subunit hypothesis. The present communication extends previous arguments along similar lines with an evaluation of more recent data. Since these data have been, or will be, published in the open literature or elsewhere in this book, they will be described here only in general terms