Volume 491 Number 7426



A way to buy time

doi: 10.1038/491637b


Misguided cancer goal

doi: 10.1038/491637a


A bleak Horizon

doi: 10.1038/491638a



Growth of ethanol fuel stalls in Brazil

doi: 10.1038/491646a


Funding protest hits Bulgarian research agency

doi: 10.1038/491649a


Space budget blow to climate science

doi: 10.1038/491645a


Daily dose of toxics to be tracked

doi: 10.1038/491647a


Microsatellites aim to fill weather-data gap

doi: 10.1038/491650a

News Features


Awash in carbon


doi: 10.1038/491654a


No going back


doi: 10.1038/491659a


After Kyoto


doi: 10.1038/491653a


Hot air


doi: 10.1038/491656a

News & Views


Computational materials science: Substitution with vision p.674


doi: 10.1038/nature11755


Plant ecology: Forests on the brink p.675


doi: 10.1038/nature11756


Earth science: Magma chambers on a slow burner p.677


doi: 10.1038/491677a


Genomics: Decoding our daily bread p.678


doi: 10.1038/491678a


Immunology: Vitamins prime immunity p.680


doi: 10.1038/491680a


Quantum physics: Strongly correlated transport p.681


doi: 10.1038/491681a



The mystery of recent stratospheric temperature trends p.692

doi: 10.1038/nature11579



The global pattern of trace-element distributions in ocean floor basalts p.698

The magmatic layers of the oceanic crust are created at constructive plate margins by partial melting of the mantle as it wells up. The chemistry of ocean floor basalts, the most accessible product of this magmatism, is studied for the insights it yields into the compositional heterogeneity of the mantle and its thermal structure. However, before eruption, parental magma compositions are modified at crustal pressures by a process that has usually been assumed to be fractional crystallization. Here we show that the global distributions of trace elements in ocean floor basalts describe a systematic pattern that cannot be explained by simple fractional crystallization alone, but is due to cycling of magma through the global ensemble of magma chambers. Variability in both major and incompatible trace-element contents about the average global pattern is due to fluctuations in the magma fluxes into and out of the chambers, and their depth, as well as to differences in the composition of the parental magmas.

doi: 10.1038/nature11678


Analysis of the bread wheat genome using whole-genome shotgun sequencing p.705

Bread wheat (Triticum aestivum) is a globally important crop, accounting for 20 per cent of the calories consumed by humans. Major efforts are underway worldwide to increase wheat production by extending genetic diversity and analysing key traits, and genomic resources can accelerate progress. But so far the very large size and polyploid complexity of the bread wheat genome have been substantial barriers to genome analysis. Here we report the sequencing of its large, 17-gigabase-pair, hexaploid genome using 454 pyrosequencing, and comparison of this with the sequences of diploid ancestral and progenitor genomes. We identified between 94,000 and 96,000 genes, and assigned two-thirds to the three component genomes (A, B and D) of hexaploid wheat. High-resolution synteny maps identified many small disruptions to conserved gene order. We show that the hexaploid genome is highly dynamic, with significant loss of gene family members on polyploidization and domestication, and an abundance of gene fragments. Several classes of genes involved in energy harvesting, metabolism and growth are among expanded gene families that could be associated with crop productivity. Our analyses, coupled with the identification of extensive genetic variation, provide a resource for accelerating gene discovery and improving this major crop.

doi: 10.1038/nature11650


A physical, genetic and functional sequence assembly of the barley genome p.711

Barley (Hordeum vulgare L.) is among the world’s earliest domesticated and most important crop plants. It is diploid with a large haploid genome of 5.1 gigabases (Gb). Here we present an integrated and ordered physical, genetic and functional sequence resource that describes the barley gene-space in a structured whole-genome context. We developed a physical map of 4.98 Gb, with more than 3.90 Gb anchored to a high-resolution genetic map. Projecting a deep whole-genome shotgun assembly, complementary DNA and deep RNA sequence data onto this framework supports 79,379 transcript clusters, including 26,159 ‘high-confidence’ genes with homology support from other plant genomes. Abundant alternative splicing, premature termination codons and novel transcriptionally active regions suggest that post-transcriptional processing forms an important regulatory layer. Survey sequences from diverse accessions reveal a landscape of extensive single-nucleotide variation. Our data provide a platform for both genome-assisted research and enabling contemporary crop improvement.

doi: 10.1038/nature11543


MR1 presents microbial vitamin B metabolites to MAIT cells p.717

Antigen-presenting molecules, encoded by the major histocompatibility complex (MHC) and CD1 family, bind peptide- and lipid-based antigens, respectively, for recognition by T cells. Mucosal-associated invariant T (MAIT) cells are an abundant population of innate-like T cells in humans that are activated by an antigen(s) bound to the MHC class I-like molecule MR1. Although the identity of MR1-restricted antigen(s) is unknown, it is present in numerous bacteria and yeast. Here we show that the structure and chemistry within the antigen-binding cleft of MR1 is distinct from the MHC and CD1 families. MR1 is ideally suited to bind ligands originating from vitamin metabolites. The structure of MR1 in complex with 6-formyl pterin, a folic acid (vitamin B9) metabolite, shows the pterin ring sequestered within MR1. Furthermore, we characterize related MR1-restricted vitamin derivatives, originating from the bacterial riboflavin (vitamin B2) biosynthetic pathway, which specifically and potently activate MAIT cells. Accordingly, we show that metabolites of vitamin B represent a class of antigen that are presented by MR1 for MAIT-cell immunosurveillance. As many vitamin biosynthetic pathways are unique to bacteria and yeast, our data suggest that MAIT cells use these metabolites to detect microbial infection.

doi: 10.1038/nature11605


Visualizing transient low-populated structures of RNA p.724

The visualization of RNA conformational changes has provided fundamental insights into how regulatory RNAs carry out their biological functions. The RNA structural transitions that have been characterized so far involve long-lived species that can be captured by structure characterization techniques. Here we report the nuclear magnetic resonance visualization of RNA transitions towards ‘invisible’ excited states (ESs), which exist in too little abundance (2–13%) and for too short a duration (45–250 μs) to allow structural characterization by conventional techniques. Transitions towards ESs result in localized rearrangements in base-pairing that alter building block elements of RNA architecture, including helix–junction–helix motifs and apical loops. The ES can inhibit function by sequestering residues involved in recognition and signalling or promote ATP-independent strand exchange. Thus, RNAs do not adopt a single conformation, but rather exist in rapid equilibrium with alternative ESs, which can be stabilized by cellular cues to affect functional outcomes.

doi: 10.1038/nature11498


宇宙:コンパクトなレンズ状銀河 NGC 1277における過度に大質量のブラックホール

An over-massive black hole in the compact lenticular galaxy NGC 1277 p.729

doi: 10.1038/nature11592


Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan p.732

doi: 10.1038/nature11611


Observing the drop of resistance in the flow of a superfluid Fermi gas p.736

doi: 10.1038/nature11613


A canonical stability–elasticity relationship verified for one million face-centred-cubic structures p.740

doi: 10.1038/nature11609


Rapid coupling between ice volume and polar temperature over the past 150,000 years p.744

doi: 10.1038/nature11593


Development of teeth and jaws in the earliest jawed vertebrates p.748

doi: 10.1038/nature11555


Global convergence in the vulnerability of forests to drought p.752

doi: 10.1038/nature11688


The genomic landscape of species divergence in Ficedula flycatchers p.756

doi: 10.1038/nature11584


A map of visual space in the primate entorhinal cortex p.761

doi: 10.1038/nature11587


Self-renewal of embryonic-stem-cell-derived progenitors by organ-matched mesenchyme p.765

doi: 10.1038/nature11463


Impaired intrinsic immunity to HSV-1 in human iPSC-derived TLR3-deficient CNS cells p.769

doi: 10.1038/nature11583


Resurrection of endogenous retroviruses in antibody-deficient mice p.774

doi: 10.1038/nature11599


Structure of the chemokine receptor CXCR1 in phospholipid bilayers p.779

doi: 10.1038/nature11580

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