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Soutenance de thèse de doctorat de l’Université de Paris
(Paris Diderot)

 

Lundi 25 novembre 2019 à 14h30

Salle de conférences de l’UMR - Ferme du Moulon, Gif-sur-Yvette

Élise TOURRETTE
École doctorale Frontières de l’Innovation en Recherche et Éducation

Unleashing genetic diversity in breedingby increasing recombination: an in silico study

 

Devant un jury composé de :

Jacques DAVID
Professeur, SupAgro, Montpellier

Rapporteur

Jean-Luc JANNINK
Professeur, Cornell University, New York, USA

Rapporteur

Thierry GRANGE
Directeur de Recherche, Institut Jacques Monod, Paris

Président

Laurence MOREAU
Directrice de Recherche, GQE-Le Moulon, Gif

Examinatrice

Olivier MARTIN
Directeur de Recherche, GQE-Le Moulon, Gif

Directeur de thèse

Matthieu FALQUE

Ingénieur de Recherche, GQE-Le Moulon, Gif

Co-directeur de thèse


 

 

Résumé

Selection, whether natural or artificial, needs genetic diversity to act. However, when it does so, it decreases the diversity by only keeping some plants. Meiotic recombination helps in maintaining a certain level of genetic diversity by shuffling allelic combinations. It also helps improving a population by putting together beneficial mutations or getting rid of deleterious ones.
The aim of my thesis was to test whether increasing recombination could help in plant breeding to slow down the loss of diversity and increase the genetic gain, by simulating plant selection and using some of the methods recently developed to increase recombination. Thus, I implemented a simulation script to test the effect of increased recombination on two scenarii used in selection: introgression of a target locus by recurrent backcrosses and recurrent genomic selection. These two approaches have been chosen as they are different and complementary for breeding, depending on the determinism of the traits considered. In recurrent genomic selection, I found an increase of up to 30% after 20 generations of selection. The highest effects were found under strong selection, with polygenic traits, and when recombination was increased in cold regions. In introgression schemes, the results were less favorable: while increasing recombination indeed hastened the introgression of the target locus, it was less efficient to remove the unwanted background.
Overall, while not all breeding scheme may benefit from increasing recombination, this approach has potential for recurrent selection.

La soutenance sera suivie d'un pot auquel vous êtes tous cordialement invités.