Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Molecular Basis Of Evolutionary Events That Shaped The Genomes Of Wheat Species (Triticum And Aegilops)

Nathalie BOUDET¹ , Mathieu CHARLES¹ , Imen MESTIRI¹ , Soazic GARDAIS¹ , Aurélie EVRARD¹ , Cécile HNEAU¹ , Harry BELCRAM¹ , Véronique CHAGUE¹ , Nathalie CHOISNE² , Sylvie SAMAIN² , Jan DVORAK³ , Boulos CHALHOUB¹

¹  Organization and evolution of plant genomes (OEPG), Unité de Recherche en Génomique végétale (URGV), 2 rue Gaston Crémieux, CP 5708, 91057 Evry, France.

²  GENOSCOPE – CNRG, 2 rue Gaston Crémieux, CP 5706, F- 91057 Evry Cedex, France

³  Dept. of Plant Sciences, UC Davis, 1 Shields Ave. Davis, CA 95616

Within the grass family (Poaceae), wheat species (genera Triticum and Aegilops) have mainly evolved through genome size increase (containing high levels of repetitive DNA) and frequent allopolyploidization events. This group of species represent an interesting model for analyzing genome organization and evolution. We are comparing genomic sequences of several selected loci between different diploid, tetraploid and hexaploid wheat species, as well as with rice and other grass species, (http://www.genoscope.cns.fr/externe/English/Projets/Projet_LE/LE.html). Genomic rearrangements such as transposable elements insertions, genomic deletions, duplications and inversions were shown to constitute the major differences between the different wheat genomes as well as between the three observed ploidy levels. This comparative analysis and further characterization of representative collections of wheat germplasms allow us to precisely determine the molecular basis of several genomic-rearrangement events. Our results suggest that most of the observed genomic rearrangements were caused by illegitimate DNA recombination mechanisms and are interestingly correlated with recent retrotransposons insertions. Comparison with the evolution of orthologous regions in rice and other grass genomes will be also discussed.