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Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus(More)
Until recently, the x86 architecture has not permitted classical trap-and-emulate virtualization. Virtual Machine Monitors for x86, such as VMware ® Workstation and Virtual PC, have instead used binary translation of the guest kernel code. However, both Intel and AMD have now introduced architectural extensions to support classical virtualization.We(More)
Most eukaryotes have genomes that exhibit high levels of gene redundancy, much of which seems to have arisen from one or more cycles of genome doubling. Polyploidy has been particularly prominent during flowering plant evolution, yielding duplicated genes (homoeologs) whose expression may be retained or lost either as an immediate consequence of(More)
Genome doubling (polyploidy) has been and continues to be a pervasive force in plant evolution. Modern plant genomes harbor evidence of multiple rounds of past polyploidization events, often followed by massive silencing and elimination of duplicated genes. Recent studies have refined our inferences of the number and timing of polyploidy events and the(More)
Mitochondrial gene content is highly variable across extant eukaryotes. The number of mitochondrial protein genes varies from 3 to 67, while tRNA gene content varies from 0 to 27. Moreover, these numbers exclude the many diverse lineages of non-respiring eukaryotes that lack a mitochondrial genome yet still contain a mitochondrion, albeit one often highly(More)
Horizontal gene transfer--the exchange of genes across mating barriers--is recognized as a major force in bacterial evolution. However, in eukaryotes it is prevalent only in certain phagotrophic protists and limited largely to the ancient acquisition of bacterial genes. Although the human genome was initially reported to contain over 100 genes acquired(More)
Allopolyploidy is a prominent mode of speciation in flowering plants. On allopolyploidy, genomic changes can take place, including chromosomal rearrangement and changes in gene expression; these processes continue over evolutionary time. Recent studies of gene expression in polyploid and hybrid plants, reviewed here, have examined expression in natural(More)
A central component of the endosymbiotic theory for the bacterial origin of the mitochondrion is that many of its genes were transferred to the nucleus. Most of this transfer occurred early in mitochondrial evolution; functional transfer of mitochondrial genes has ceased in animals. Although mitochondrial gene transfer continues to occur in plants, no(More)
Flowering plants (angiosperms) are by far the largest, most diverse, and most important group of land plants, with over 250,000 species and a dominating presence in most terrestrial ecosystems. Understanding the origin and early diversification of angiosperms has posed a long-standing botanical challenge [1]. Numerous morphological and molecular systematic(More)
Hybridization is a prominent process among natural plant populations that can result in phenotypic novelty, heterosis, and changes in gene expression. The effects of intraspecific hybridization on F1 hybrid gene expression were investigated using parents from divergent, natural populations of Cirsium arvense, an invasive Compositae weed. Using an RNA-seq(More)