description
- In the framework of studies of the organization and evolution of the bread wheat genome, the host team has developed a large project aiming to characterize its largest chromosome, 3B, at the molecular level. A physical map of this giant chromosome (about the size of the soybean genome) was established in 2008 (Paux et al., 2008). Recently, in a pilot study prior to the complete chromosome sequencing (3BSEQ project), the host group produced and analyzed precisely 18 Mb of contiguous sequences representing the first large sample sequences available for the hexaploid wheat genome. The results showed that about 50% of the genes and pseudogenes identified in wheat are not collinear with the other grass genomes raising several questions about their origin, fate and expression in the wheat genome. The objectives of this project are to select a number of non collinear genes in different structural contexts and (i) determine whether these genes originate from interchromosomal duplications of genes ancestrally present at distant loci, (ii) investigate the molecular mechanisms and evolutionary forces involved in the shuffling of the gene content, including transposable elements, and (iii) analyze their expression patterns relative to collinear genes through qRT-PCR experiments and analysis of RNA Seq data that will be produced in the 3BSEQ project on 15 different RNA samples. We will investigate the molecular evolution of their sequences in a hexaploid context where homoeologous and paralogous gene copies are maintained.