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Olivier Martin

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Rozenn Le Guyader

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Thierry Balliau

SémIDEEV de l’UMR

Génétique Quantitative et Évolution – Le Moulon

ATTENTION !
Séminaire délocalisé à l’ESE, salle de conférences, Bât. 362, Campus d’Orsay

Vendredi 10 mars 2017

12h00

Éric  JENCZEWSKI
IJPB, Inra- Versailles
in collaboration with Andrew Lloyd and many others

invité par Olivier Martin et Matthieu Falque
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" Crossing-over boundaries:
the complex interplay between
meiotic recombination and polyploidy "

Résumé

Meiotic recombination ensures both faithful chromosome transmission and allelic shuffling over generations. Although considerable progress has been made in deciphering the molecular mechanisms of meiotic recombination in model plant species, much of that work has largely disregarded the special features of crop genomes like polyploidy (i.e. Whole-Genome Duplication). There are, however, many different ways of looking at the complex interplay between polyploidy and meiotic recombination. On the one hand, polyploidy leads to initial meiotic gene duplication and therefore provides opportunities to “enrich the meiotic tool-kit”. On the other hand, polyploidy challenges faithful chromosome segregation as it gives every chromosome more than a single possible partner to recombine with; polyploidy therefore requires meiotic adaptations. In this talk, I will outline two examples illustrating the complex interplay between polyploidy and meiotic recombination. I will first show that meiotic recombination gene duplicates tend to return rapidly to a single copy post WGD and provide evidence that even rapidly lost meiotic recombination duplicates are unlikely to be detrimental. I will then show that homo(e)ologous chromosome sorting is still an error-prone process in extent allopolyploids, resulting in exchanges of large chromosomal segments between homoeologous chromosomes. Our results indicate that these homoeologous exchanges have dramatic initial impacts on both gene content and dosage dependent gene expression in Brassica napus, a representative allotetraploid crop. Altogether, these two examples illustrate the long and short-term combined consequences of polyploidy and meiotic recombination.