Reducing MSH4 copy number prevents meiotic crossovers between non-homologous chromosomes in Brassica napus

Adrián Gonzalo, Marie-Odile Lucas, Catherine Charpentier, Greta Sandmann, Andrew Lloyd, Eric Jenczewski

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34 Citations (SciVal)
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In allopolyploids, correct chromosome segregation requires suppression of non-homologous crossovers while levels of homologous crossovers are ensured. To date, no mechanism able to specifically inhibit non-homologous crossovers has been described in allopolyploids other than in bread wheat. Here, we show that reducing the number of functional copies of MSH4, an essential gene for the main crossover pathway, prevents non-homologous crossovers in allotetraploid Brassica napus. We show that non-homologous crossovers originate almost exclusively from the MSH4-dependent recombination pathway and that their numbers decrease when MSH4 returns to single copy in B. napus; by contrast, homologous crossovers remain unaffected by MSH4 duplicate loss. We also demonstrate that MSH4 systematically returns to single copy following numerous independent polyploidy events, a pattern that is probably not by chance. These results suggest that stabilization of allopolyploid meiosis can be enhanced by loss of a key meiotic recombination gene.

Original languageEnglish
Article number2354
Number of pages9
JournalNature Communications
Issue number1
Early online date29 May 2019
Publication statusPublished - 01 Dec 2019


  • Brassica napus/genetics
  • Chromosome Segregation/genetics
  • Chromosomes, Plant/metabolism
  • Crossing Over, Genetic/genetics
  • DNA Copy Number Variations
  • Homologous Recombination
  • Meiosis/genetics
  • MutS Proteins/genetics
  • Polyploidy


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