title: Crossover rate between homologous chromosomes and interference are regulated by the addition of specific unpaired chromosomes in Brassica.
abstract: Recombination is a major mechanism generating genetic diversity, but the control of the crossover rate remains a key question. In Brassica napus (AACC, 2n = 38), we can increase the homologous recombination between A genomes in AAC hybrids. Hypotheses for this effect include the number of C univalent chromosomes, the ratio between univalents and bivalents and, finally, which of the chromosomes are univalents. To test these hypotheses, we produced AA hybrids with zero, one, three, six or nine additional C chromosomes and four different hybrids carrying 2n = 32 and 2n = 35 chromosomes. The genetic map lengths for each hybrid were established to compare their recombination rates. The rates were 1.4 and 2.7 times higher in the hybrids having C6 or C9 alone than in the control (0C). This enhancement reached 3.1 and 4.1 times in hybrids carrying six and nine C chromosomes, and it was also higher for each pair of hybrids carrying 2n = 32 or 2n = 35 chromosomes, with a dependence on which chromosomes remained as univalents. We have shown, for the first time, that the presence of one chromosome, C9 , affects significantly the recombination rate and reduces crossover interference. This result will have fundamental implications on the regulation of crossover frequency.
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Loreto
authors.initials: L
authors.lastname: Suay
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.|Beijing Vegetable Research Center (BVRC) of BAAFS, National Engineering Research Center for Vegetables (NERCV), 50 Zhanghua Street, Haidian District, PO Box 2443, Beijing , 100097, China.
authors.forename: Deshuang
authors.initials: D
authors.lastname: Zhang
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Eber
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Jouy
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Maryse
authors.initials: M
authors.lastname: Lodé
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Huteau
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Coriton
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Szadkowski
authors.affiliation: CETIOM, Avenue Lucien Brétignières, Campus de Grignon, F-78850, Thiverval Grignon, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Leflon
authors.affiliation: INRA, UMR0320 INRA-CNRS-Université Paris XI-AgroParisTech, Génétique Végétale, Ferme du Moulon, 91190, Gif sur Yvette, France.
authors.forename: Olivier C
authors.initials: OC
authors.lastname: Martin
authors.affiliation: INRA, UMR0320 INRA-CNRS-Université Paris XI-AgroParisTech, Génétique Végétale, Ferme du Moulon, 91190, Gif sur Yvette, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Falque
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Bâtiment 7, INRA Centre de Versailles-Grignon, Route de St-Cyr (RD10), 78026, Versailles Cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Jenczewski
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Paillard
authors.affiliation: INRA, UMR 1349, Institut de Génétique, Environnement et Protection des plantes, BP 35327, F-35653, Le Rheu Cedex, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Chèvre
mesh_terms: D000782:Aneuploidy; D029688:Brassica napus / Q000235:genetics*; D023902:Chromosome Pairing; D032461:Chromosomes, Plant / Q000378:metabolism*; D059765:Homologous Recombination; D006824:Hybridization, Genetic; D017404:In Situ Hybridization, Fluorescence
keywords: Brassica; crossover rate; homologous recombination; inter-specific hybrids; interference; polyploidy