Use of a recombination reporter insert to define meiotic recombination domains on chromosome III of Saccharomyces cerevisiae

In Saccharomyces cerevisiae, meiotic recombination is initiated by DNA doub le-strand breaks (DSBs). DSBs usually occur in intergenic regions that disp lay nuclease hypersensitivity in digests of chromatin. DSBs are distributed nonuniformly across chromosomes; on chromosome III, DSBs are concentrated in two "hot" regions, one in each chromosome arm. DSBs occur rarely in regi ons within about 40 kb of each telomere and in an 80-kb region in the cente r of the chromosome, just to the right of the centromere. We used recombina tion reporter inserts containing arg4 mutant alleles to show that the "cold " properties of the central DSB-deficient region are imposed on DNA inserte d in the region. Cold region inserts display DSB and recombination frequenc ies that are substantially less than those seen with similar inserts in fla nking hot regions. This occurs without apparent change in chromatin structu re, as the same pattern and level of DNase I hypersensitivity is seen in ch romatin of hot and cold region inserts. These data are consistent with the suggestion that features of higher-order chromosome structure or chromosome dynamics act in a target sequence-independent manner to control where reco mbination events initiate during meiosis.