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 Schizosaccharomyces pombe. In a repair defective mutant, carrying a in the mutation in the RecA 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.