Double-strand breaks can initiate meiotic recombination in S. cerevisiae.
We investigated the effects of double-strand breaks on meiotic recombination in yeast. A double-strand break was introduced at the MATa locus by sporulation of a MAT alpha inc/MATa diploid under inducing conditions for the HO-encoded endonuclease; 14% of the resulting tetrads had undergone 4 alpha:0a conversion. Conversion at MAT was associated with co-conversion of a closely linked marker and an increased recombination frequency for flanking markers. We also studied the sporulation products of a diploid heterozygous at the HIS4 locus for an insertion of a 100 bp fragment of MATa containing the HO endonuclease cut site. Under inducing conditions, a significant number of tetrads were formed that had undergone gene conversions in favor of the HIS4+ allele. Although double-strand breaks can initiate meiotic recombination in yeast, the data suggest that they do not normally do so.
D004247:DNA / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics*; D005785:Gene Conversion; D008540:Meiosis; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D004271:DNA, Fungal; D004247:DNA