Unscheduled DNA synthesis (DNA repair) in the germ cells of male mice--its role in the study of mammalian mutagenesis.

Unscheduled DNA synthesis (UDS) has been found to occur in vivo in specific meiotic and postmeiotic germ cell stages of male mice after mutagen treatment. Techniques and problems involved in measuring UDS are discussed, including the administration of tritium-labeled thymidine ([3H]dT) and mutagens, and the detection of UDS using liquid scintillation counting (LSC) and autoradiography. The sensitivity of detection of UDS in the male germ cells is compared to that of other genetic end points, and the possible role of UDS in the actual repair of genetic damage is considered. Possible areas for future research on the role of UDS in repair of genetic damage in the mouse are suggested.