title: High-resolution mapping of spontaneous mitotic recombination hotspots on the 1.1 Mb arm of yeast chromosome IV.
abstract: Although homologous recombination is an important pathway for the repair of double-stranded DNA breaks in mitotically dividing eukaryotic cells, these events can also have negative consequences, such as loss of heterozygosity (LOH) of deleterious mutations. We mapped about 140 spontaneous reciprocal crossovers on the right arm of the yeast chromosome IV using single-nucleotide-polymorphism (SNP) microarrays. Our mapping and subsequent experiments demonstrate that inverted repeats of Ty retrotransposable elements are mitotic recombination hotspots. We found that the mitotic recombination maps on the two homologs were substantially different and were unrelated to meiotic recombination maps. Additionally, about 70% of the DNA lesions that result in LOH are likely generated during G1 of the cell cycle and repaired during S or G2. We also show that different genetic elements are associated with reciprocal crossover conversion tracts depending on the cell cycle timing of the initiating DSB.
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America.
authors.forename: Jordan
authors.initials: J
authors.lastname: St Charles
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Petes
mesh_terms: D002453:Cell Cycle / Q000235:genetics; D002455:Cell Division; D002874:Chromosome Mapping; D015825:Chromosomes, Fungal / Q000235:genetics; D003434:Crossing Over, Genetic; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D059765:Homologous Recombination / Q000235:genetics*; D019656:Loss of Heterozygosity / Q000235:genetics; D008938:Mitosis / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics