Genomes behave as social entities: Alien chromatin minorities evolve through specificities reduction

In a paper to be published in the August issue of Theoretical and Applied Genetics, the authors report how they detected a high level of genomic restructuring events affecting rye chromosomes added to wheat genome through microsatellite and retrotransposon PCR-based molecular marker techniques. In another work (Bento et al 2008. PLoS ONE 3(1): e1402), the same authors had previously identified genomic alterations affecting preferentially rye genome in triticale, the hybrid genotype that results from the union of wheat and rye entire genomes.

Plant breeders commonly produce hybrid genotypes, through the cross of related species, to obtain improved varieties. This phenomenon – polyploidization -- occurred also repeatedly during plant evolution. Triticale, the polyploid cereal that has been synthesized by the cross between wheat and rye, is one of the better studied polyploid model systems.

The novelty of this work, which may have important implications in future plant breeding strategies, is to show that genomes behave as social entities. In fact, reduced amounts of introgressed rye chromatin in wheat-rye addition lines, which possess only one rye chromosome pair, are more exposed to genomic restructuring than in triticale.