In an article, “Analysis of the bread wheat genome using whole-genome shotgun sequencing”, published 29 Nov. ’12 in Nature 491: 705-710, twenty-nine scientists affiliated to ten leading institutions of the UK, the USA and Germany under the guidance of Michael W. Bevan assembled gene sequences of hexaploid bread wheat, Triticum aestivum (2n=6x=42). This work was carried out in collaboration with Neil Hall and Anthony Hall (Liverpool University), Keith Edwards and Gary Barker (University of Bristol), Paul Kersey and Ewan Birney (European Bioinformatics Institute) Klaus Mayer (IBIS, Helmholz-Zentrum, Munich), Dick McCombie (Cold Spring Harbor Laboratory), Jane Rogers and Mario Caccamo (The Genome Analysis Centre), Jan Dvorak (UC, Davis) and Bikram Gill (Kansas State University).
The bread wheat is constituted of two sets of chromosomes of each of A, B and D genome. Using 454 pyro-sequencing these authors have reported the sequencing of its large, 17-gigabase-pair, hexaploid genome. They compared the sequencing with of diploid ancestral and progenitor genomes, A, B and D. Of about 94 -96,000 genes the investigators assigned two-thirds to the three component genomes A, B and D. However, under high-resolution study many small disruptions were observed in the conserved gene order. Synteny (synteny describes the physical co-localization of genetic loci on the same chromosome) maps were also identified. Furthermore, in spite of the bread wheat being allohexploid the genome was found to be highly dynamic as a result of significant loss of gene family members on polyploidization and domestication. An abundance of gene fragments also characterize this species. The authors were able to associate several classes of genes involved in energy harvesting, metabolism and growth – important factors involved in crop productivity. The authors believe that their analyses may prove to be a rich source for enhancing gene discovery leading to further improvement of this staple crop which provides food to the majority of world population.