Genomics of tetraploid wheat domestication

摘要

The domestication of plants represents one of the most important events in the development of human culture, We have used cDNA microarrays to study the alterations in gene expression that occurred during wheat domestication and we have compared the range of variation in the transcriptome of wild (Triticum turgidum ssp. dicoccoides) versus domestic wheat (T. turgidum ssp. dicoccum and ssp. durum). The frequency of genes differentially expressed was 2.53% in young spikes. A high proportion of the genesthat were up-regulated in domestic wheat were related to carbon metabolism. Genes preferentially expressed in the wild included several storage protein genes. Finally, we determined the variation in levels of gene expression for each of the 2,493 genesstudied. About 23% of the genes were polymorphic in levels of expression in the different lines. The intra-specific variation in gene expression within ssp. dicoccoides was about four times higher than within the domesticated species. That reduction in variation during domestication is in the same range as that found at the genomic level, for nucleotide polymorphism. Nevertheless, we found that certain genes were more variables in the domestic varieties than in the wild. This suggests the possibility that selection under domestication led to the fixation of new mutations that did not previously exist in the wild. In summary, this work showed that high throughput expression analysis of genes provides much insight into evolutionary studies on the geneticstructure of wild population, on biodiversity as well as on evolution under domestication.