An improved method for DNA alkaline gradient analysis and its application to the effect of carcinogens on mouse liver DNA.

An alkaline sodium iodide density gradient technique is described, for use in sedimentation rate centrifugation studies of in vivo induction of single strand breaks in DNA. The combination of this type of gradient with a sensitive fluorometric DNA estimation makes it possible to analyze very small amounts of DNA without any need for labeling the nucleic acid with radioactive thymidine.