Meiotic recombination remote from prominent DNA break sites in S. pombe

DNA breakage is intimately associated with meiotic recombination in the fission yeast Schizosaccharomyces pombe. Sites of prominent DNA breakage were found similar to25 to similar to200 kb apart in the genomic regions surveyed. We examined in detail a 501 kb region of chromosome I and found six sites, or tight clusters of sites, at which similar to2%-11% of the DNA accumulated breaks in a rad50S mutant. In contrast to the discrete, widely spaced distribution of prominent break sites, recombination in this region was more uniformly distributed (0.7-1.6 cM/10 kb) whether the genetic interval tested contained no, one, or more such sites. We Infer that although recombination depends upon DNA breakage, recombination often occurs remote from these sites (tens of kilobases away); we discuss mechanisms by which this may occur.