Meiotic double-strand breaks in Schizosaccharomyces pombe

Meiotic DNA double-strand breaks (DSBs) are associated with recombination hot spots in the yeast Saccharomyces cerevisiae and are believed to initiate the process of recombination, Until now. meiosis-induced breaks have not been shown to occur regularly in other organisms. Here we show, by pulsed-field gel electrophoresis of DNA, that meiotic DSBs occur transiently in all three chromosomes of the fission yeast Schizo-saccharomyces pombe. In a repair defective mutant, carrying a mutation in the Rec A homolog gene rhp51, meiotic DSBs accumulate. In contrast to expectation from the genetic map of S. pombe however, many chromosomal DNA molecules remain unbroken during meiosis.