Extensive 3'-overhanging, single-stranded DNA associated with the meiosis-specific double-strand breaks at the ARG4 recombination initiation site

Cell. 1991 Mar 22;64(6):1155-61. doi: 10.1016/0092-8674(91)90270-9.


Meiosis-specific double-strand breaks occur at the initiation site for meiotic gene conversion in the yeast ARG4 gene. Here we show that the break fragments end in extensive 3'-overhanging, single-stranded tails. The single-stranded tails very in length, generating a gradient of single-strandedness that parallels the gradient of gene conversion frequencies in ARG4. In strains carrying a rad50S mutation, which blocks meiotic recombination, the extensive single-stranded tails do not form, suggesting that their generation is an obligatory step in meiotic recombination. Using the rad50S mutant, we have mapped the site of the ARG4 break to a small region within the genetically defined recombination initiation site. These results strongly support the double-strand break model of meiotic recombination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA, Fungal / physiology*
  • DNA, Single-Stranded / physiology*
  • Gene Conversion
  • Genes, Fungal / genetics
  • Meiosis
  • Mutation
  • Recombination, Genetic / genetics*
  • Saccharomyces cerevisiae / genetics*


  • DNA, Fungal
  • DNA, Single-Stranded