Projet ANR-07-BLAN-0215 – COPATH : Unraveling crossover pathways with Arabidopsis thaliana and crop relatives
Programme : Blanc (BLANC) 2007
Année de financement : 2007
Coordinateur du projet : (INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE - CENTRE DE RECHERCHE DE VERSAILLES GRIGNON)
Partenaires : Institut national de la recherche agronomique; Institut national de la recherche agronomique; Institut national de la recherche agronomique; Institut national de la recherche agronomique
Montant : 460000.0 euros
Date de début : 2007
Durée : 48 mois
Résumé : Crossovers (COs) lead to the reciprocal exchange of large fragments of genetic material between homologous chromosomes occurring during meiosis. Data from various model organisms show that the distribution of COs is not random along chromosomes. The current view is that the final distribution of COs is the result of several constraints that can be summarized as follows: (i) The density of DNA double strand breaks that initiate meiotic recombination varies along chromosomes. (ii) Their individual penchant to become a CO or a NCO is probably variable. (iii) Interference strength varies within and from chromosome to chromosome and probably acts on several levels. (iv) Some COs are insensitive to interference, their proportion differing from species to species. (v) There may be more than two pathways controlling CO formation. (vi) Density of COs on a bivalent may be modulated by a global cellular control. To obtain a coherent view of molecular components and mechanisms involved in CO formation and distribution, we propose to study in parallel the actors and the distribution of this process using Arabidopsis thaliana as model. We will study the different steps and pathways of meiotic recombination through (i) the isolation and characterization of meiotic mutants, (ii) the description of CO density and distribution genome-wide in wild-type, (iii) the analysis of the effect of different mutations on CO distribution, and (iv) the use of modeling approaches to integrate results obtained from the previous points. Studies in the closest crop relatives of Arabidopsis thaliana, diploid and tetraploid Brassica species, will allow us to investigate the effect of adding one or several supplementary chromosomes on the final CO distribution. The integration of the results obtained by these approaches will provide a genomic-wide understanding of the constraints on meiotic COs formation and localization.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ...