Identification of joint molecules that form frequently between homologs but rarely between sister chromatids during yeast meiosis

Cell. 1994 Jan 14;76(1):51-63. doi: 10.1016/0092-8674(94)90172-4.


We have investigated DNA interactions between homologs and between sister chromatids during meiosis in S. cerevisiae. We have detected a DNA species containing information from both parental chromosomes at a specific hotspot for meiotic recombination and double strand breaks (DSBs). These joint molecules are a prominent feature of meiotic prophase. They appear to be a major intermediate stage in DSB-promoted recombination, because they occur with appropriate timing and require known recombination functions. Other possibilities cannot be completely dismissed, however. Most or all joint molecules contain two full-length nonrecombinant strands from each parental duplex and thus do not consist of single Holliday junctions. Joint molecules form between sister chromatids at approximately 10% the interhomolog level. Also, joint molecule formation is aberrant in a mutant defective in the HOP1 gene, which encodes a meiotic chromosome structure component. General models for discrimination between homologs and sisters during meiosis are discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blotting, Southern
  • Chromatids / physiology*
  • DNA, Fungal / isolation & purification
  • DNA, Fungal / metabolism*
  • Electrophoresis, Gel, Two-Dimensional
  • Genes, Fungal
  • Heterozygote
  • Homozygote
  • Meiosis
  • Nucleic Acid Heteroduplexes / isolation & purification
  • Nucleic Acid Heteroduplexes / metabolism*
  • Recombination, Genetic*
  • Restriction Mapping
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Sister Chromatid Exchange*


  • DNA, Fungal
  • Nucleic Acid Heteroduplexes