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Recombination hotspots flank the Cryptococcus mating-type locus: implications for the evolution of a fungal sex chromosome.

Publication ,  Journal Article
Hsueh, Y-P; Idnurm, A; Heitman, J
Published in: PLoS Genet
November 3, 2006

Recombination increases dramatically during meiosis to promote genetic exchange and generate recombinant progeny. Interestingly, meiotic recombination is unevenly distributed throughout genomes, and, as a consequence, genetic and physical map distances do not have a simple linear relationship. Recombination hotspots and coldspots have been described in many organisms and often reflect global features of chromosome structure. In particular, recombination frequencies are often distorted within or outside sex-determining regions of the genome. Here, we report that recombination is elevated adjacent to the mating-type locus (MAT) in the pathogenic basidiomycete Cryptococcus neoformans. Among fungi, C. neoformans has an unusually large MAT locus, and recombination is suppressed between the two >100-kilobase mating-type specific alleles. When genetic markers were introduced at defined physical distances from MAT, we found the meiotic recombination frequency to be approximately 20% between MAT and a flanking marker at 5, 10, 50, or 100 kilobases from the right border. As a result, the physical/genetic map ratio in the regions adjacent to MAT is distorted approximately 10- to 50-fold compared to the genome-wide average. Moreover, recombination frequently occurred on both sides of MAT and negative interference between crossovers was observed. MAT heterozygosity was not required for enhanced recombination, implying that this process is not due to a physical distortion from the two non-paired alleles and could also occur during same-sex mating. Sequence analysis revealed a correlation between high G + C content and these hotspot regions. We hypothesize that the presence of recombinational activators may have driven several key events during the assembly and reshaping of the MAT locus and may have played similar roles in the origins of both metabolic and biosynthetic gene clusters. Our findings suggest that during meiosis the MAT locus may be exchanged onto different genetic backgrounds and therefore have broad evolutionary implications with respect to mating-type switching in both model and pathogenic yeasts.

Duke Scholars

Published In

PLoS Genet

DOI

EISSN

1553-7404

Publication Date

November 3, 2006

Volume

2

Issue

11

Start / End Page

e184

Location

United States

Related Subject Headings

  • Sequence Deletion
  • Recombination, Genetic
  • Meiosis
  • Genes, Mating Type, Fungal
  • Evolution, Molecular
  • Developmental Biology
  • DNA, Fungal
  • Cryptococcus neoformans
  • Crossing Over, Genetic
  • Chromosomes, Fungal
 

Citation

APA
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ICMJE
MLA
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Hsueh, Y.-P., Idnurm, A., & Heitman, J. (2006). Recombination hotspots flank the Cryptococcus mating-type locus: implications for the evolution of a fungal sex chromosome. PLoS Genet, 2(11), e184. https://doi.org/10.1371/journal.pgen.0020184
Hsueh, Yen-Ping, Alexander Idnurm, and Joseph Heitman. “Recombination hotspots flank the Cryptococcus mating-type locus: implications for the evolution of a fungal sex chromosome.PLoS Genet 2, no. 11 (November 3, 2006): e184. https://doi.org/10.1371/journal.pgen.0020184.
Hsueh, Yen-Ping, et al. “Recombination hotspots flank the Cryptococcus mating-type locus: implications for the evolution of a fungal sex chromosome.PLoS Genet, vol. 2, no. 11, Nov. 2006, p. e184. Pubmed, doi:10.1371/journal.pgen.0020184.

Published In

PLoS Genet

DOI

EISSN

1553-7404

Publication Date

November 3, 2006

Volume

2

Issue

11

Start / End Page

e184

Location

United States

Related Subject Headings

  • Sequence Deletion
  • Recombination, Genetic
  • Meiosis
  • Genes, Mating Type, Fungal
  • Evolution, Molecular
  • Developmental Biology
  • DNA, Fungal
  • Cryptococcus neoformans
  • Crossing Over, Genetic
  • Chromosomes, Fungal