title: Differential timing and control of noncrossover and crossover recombination during meiosis.
abstract: Unitary models of meiotic recombination postulate that a central intermediate containing Holliday junctions is resolved to generate either noncrossover or crossover recombinants, both of which contain heteroduplex DNA. Contrary to this expectation, we find that during meiosis in Saccharomyces cerevisiae, noncrossover heteroduplex products are formed at the same time as Holliday junction intermediates. Crossovers appear later, when these intermediates are resolved. Furthermore, noncrossover and crossover recombination are regulated differently. ndt80 mutants arrest in meiosis with unresolved Holliday junction intermediates and very few crossovers, while noncrossover heteroduplex products are formed at normal levels and with normal timing. These results suggest that crossovers are formed by resolution of Holliday junction intermediates, while most noncrossover recombinants arise by a different, earlier pathway.
authors.affiliation: Laboratory of Biochemistry, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: T
authors.initials: T
authors.lastname: Allers
authors.forename: M
authors.initials: M
authors.lastname: Lichten
mesh_terms: D001483:Base Sequence; D003434:Crossing Over, Genetic; D004261:DNA Replication; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics*; D007700:Kinetics; D008540:Meiosis; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D013172:Spores, Fungal; D014157:Transcription Factors
chemical_list: D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C097071:NDT80 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors