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Nat Commun. 2019 May 29;10(1):2354. doi: 10.1038/s41467-019-10010-9.

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

Author information

1
Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France.
2
Department of Cell and Developmental Biology, John Innes Centre, Norwich, NR4 7UH, UK.
3
INRA UMR1349 Institut de Génétique, Environnement et Protection des Plantes, Le Rheu, 35653, France.
4
Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3EB, UK.
5
Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France. eric.jenczewski@inra.fr.

Abstract

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.

PMID:
31142748
PMCID:
PMC6541637
DOI:
10.1038/s41467-019-10010-9
[Indexed for MEDLINE]
Free PMC Article

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