The objective of this project is to develop methods to detect translocation carriers in populations of mice treated with potential mutagens by evaluating the DNA distributions of sperm. The Axiomat scanning microscope is being used to quantitate the DNA fluorescence of single sperm and spermatids. The measured distributions of DNA fluorescence of single sperm and spermatids. The measured distributions of DNA fluorescence are being evaluated within and between normal mice and those carrying known translocations. Work has begun to examine the feasibility of automatic systems of measurement and analysis.