title: A whole-genome snapshot of 454 sequences exposes the composition of the barley genome and provides evidence for parallel evolution of genome size in wheat and barley.
abstract: The genomes of barley and wheat, two of the world's most important crops, are very large and complex due to their high content of repetitive DNA. In order to obtain a whole-genome sequence sample, we performed two runs of 454 (GS20) sequencing on genomic DNA of barley cv. Morex, which yielded approximately 1% of a haploid genome equivalent. Almost 60% of the sequences comprised known transposable element (TE) families, and another 9% represented novel repetitive sequences. We also discovered high amounts of low-complexity DNA and non-genic low-copy DNA. We identified almost 2300 protein coding gene sequences and more than 660 putative conserved non-coding sequences. Comparison of the 454 reads with previously published genomic sequences suggested that TE families are distributed unequally along chromosomes. This was confirmed by in situ hybridizations of selected TEs. A comparison of these data for the barley genome with a large sample of publicly available wheat sequences showed that several TE families that are highly abundant in wheat are absent from the barley genome. This finding implies that the TE composition of their genomes differs dramatically, despite their very similar genome size and their close phylogenetic relationship.
authors.affiliation: Institute of Plant Biology, University Zurich, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wicker
authors.forename: Stefan
authors.initials: S
authors.lastname: Taudien
authors.forename: Andreas
authors.initials: A
authors.lastname: Houben
authors.forename: Beat
authors.initials: B
authors.lastname: Keller
authors.forename: Andreas
authors.initials: A
authors.lastname: Graner
authors.forename: Matthias
authors.initials: M
authors.lastname: Platzer
authors.forename: Nils
authors.initials: N
authors.lastname: Stein
mesh_terms: D004251:DNA Transposable Elements; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D018745:Genome, Plant; D001467:Hordeum / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014908:Triticum / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D018744:DNA, Plant