Meiotic genes: how do they evolve in hexaploid wheat?

In most eukaryotes, meiotic recombination plays a fundamental role in ensuring correct segregation of the chromosomes during gamete formation and for generating diversity in the progeny. Meiotic recombination is then crucial for plant breeding because it allows, through the crossovers, to reshuffle genetic material between individuals and between species. Genes involved in meiosis remains poorly studied in polyploids and we can wonder if polyploidy affects meiotic genes in bread wheat. We first analysed in silico in sequenced-monocotyledonous species  64 genes known to be involved in the meiotic process in Arabidopsis in order to identify how many copies of each gene are present in each species. Preliminary results show that most of the meiotic genes exist in only one copy in the monocots with some differences depending on the species. However, a few genes were also found to be highly tandemly repeated. We focused on a subset (18) of these genes to study how they behave in wheat to estimate their evolution and draw a pattern of gene loss or retention. The homoeologous copies will be isolated by screening a Chinese Spring BAC library and their expression will be measured during five stages representing the early steps of the meiosis. Finally, the genetic variability of the various copies of these genes will be evaluated in a large core collection. In conclusion, the study of meiotic genes should provide keys to better understand the control of meiosis in polyploid wheat and allow in fine to monitor recombination in breeding program.