Zenvirth, D., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
Arbel, T., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
Sherman, A., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
Goldway, M., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
Klein, S., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
Simchen, G., Department of Genetics, Hebrew University of Jerusalem, Jerusalem 91904, Israel

We present a scheme for locating double-strand breaks (DSBs) in meiotic chromosomes of Saccharomyces cerevisiae, based on the separation of large DNA molecules by pulsed field gel electrophoresis. Using a rad50S mutant, in which DSBs are not processed, we show that DSBs are widely induced in S.cerevisiae chromosomes during meiosis. Some of the DSBs accumulate at certain preferred sites. We present general profiles of DSBs in chromosomes III, V, VI and VII. A map of the 12 preferred sites on chromosome III is presented. At least some of these sites correlate with known 'hot spots' for meiotic recombination. The data are discussed in view of current models of meiotic recombination and chromosome segregation.