High-resolution mapping of meiotic crossovers and non-crossovers in yeast

• Published in: Nature Vol. 454; no. 7203; pp. 479 - 485
• Main Authors: Mancera, Eugenio, Bourgon, Richard, Brozzi, Alessandro, Huber, Wolfgang, Steinmetz, Lars M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.07.2008; Nature Publishing; Nature Publishing Group
• Subjects: Animals; Biological and medical sciences; Brewer's yeast; Chromosome Mapping; Chromosomes, Fungal; Chromosomes, Fungal - genetics; Classical genetics, quantitative genetics, hybrids; crossing over; Crossing over (Genetics); Crossing Over, Genetic; Crossing Over, Genetic - genetics; crossover-associated gene conversion; cytology; DNA Breaks, Double-Stranded; DNA-Binding Proteins; DNA-Binding Proteins - genetics; Flap Endonucleases; Fundamental and applied biological sciences. Psychology; gene conversion; Gene Conversion - genetics; Gene Expression Regulation, Fungal; Genetic aspects; Genetic diversity; Genetic Linkage; Genetic Linkage - genetics; Genetic Markers; Genetic Markers - genetics; Genetic recombination; genetics; Genetics of eukaryotes. Biological and molecular evolution; Genome, Fungal; Genome, Fungal - genetics; Genomics; Genotype; Haplotypes; Haplotypes - genetics; homologous recombination; Humanities and Social Sciences; Invertebrata; Meiosis; Meiosis - genetics; Methods; multidisciplinary; Mutation; Mutation - genetics; non-crossover gene conversion; non-crossovers; Observations; Saccharomyces cerevisiae; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; Saccharomyces cerevisiae Proteins - genetics; Science; Trans-Activators; Trans-Activators - genetics; Yeast; Yeasts; United Kingdom; Ascomycota; Fungi; Genetic mapping; High resolution; Recombination; Yeast; Meiosis; Gene conversion; Crossing over; Saccharomyces cerevisiae
• ISSN: 0028-0836; 1476-4687; 1476-4687; 1476-4679
• DOI: 10.1038/nature07135

Meiotic recombination has a central role in the evolution of sexually reproducing organisms. The two recombination outcomes, crossover and non-crossover, increase genetic diversity, but have the potential to homogenize alleles by gene conversion. Whereas crossover rates vary considerably across the genome, non-crossovers and gene conversions have only been identified in a handful of loci. To examine recombination genome wide and at high spatial resolution, we generated maps of crossovers, crossover-associated gene conversion and non-crossover gene conversion using dense genetic marker data collected from all four products of fifty-six yeast (Saccharomyces cerevisiae) meioses. Our maps reveal differences in the distributions of crossovers and non-crossovers, showing more regions where either crossovers or non-crossovers are favoured than expected by chance. Furthermore, we detect evidence for interference between crossovers and non-crossovers, a phenomenon previously only known to occur between crossovers. Up to 1% of the genome of each meiotic product is subject to gene conversion in a single meiosis, with detectable bias towards GC nucleotides. To our knowledge the maps represent the first high-resolution, genome-wide characterization of the multiple outcomes of recombination in any organism. In addition, because non-crossover hotspots create holes of reduced linkage within haplotype blocks, our results stress the need to incorporate non-crossovers into genetic linkage analysis.