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The $2.4-billion plan to steal a rock from Mars 

Nature ( IF 38.138 ) 2017-01-19

Alexandra Witze 


NASA is now building the rover that it hopes will bring back signs of life on the red planet.

A theoretical foundation for multi-scale regular vegetation patterns 

Nature ( IF 38.138 ) 2017-01-18

Corina E. Tarnita, Juan A. Bonachela, Efrat Sheffer, Jennifer A. Guyton, Tyler C. Coverdale, Ryan A. Long, Robert M. Pringle 


Self-organized regular vegetation patterns are widespread and thought to mediate ecosystem functions such as productivity and robustness, but the mechanisms underlying their origin and maintenance remain disputed. Particularly controversial are landscapes of overdispersed (evenly spaced) elements, such as North American Mima mounds, Brazilian murundus, South African heuweltjies, and, famously, Namibian fairy circles. Two competing hypotheses are currently debated. On the one hand, models of scale-dependent feedbacks, whereby plants facilitate neighbours while competing with distant individuals, can reproduce various regular patterns identified in satellite imagery. Owing to deep theoretical roots and apparent generality, scale-dependent feedbacks are widely viewed as a unifying and near-universal principle of regular-pattern formation despite scant empirical evidence. On the other hand, many overdispersed vegetation patterns worldwide have been attributed to subterranean ecosystem engineers such as termites, ants, and rodents. Although potentially consistent with territorial competition, this interpretation has been challenged theoretically and empirically and (unlike scale-dependent feedbacks) lacks a unifying dynamical theory, fuelling scepticism about its plausibility and generality. Here we provide a general theoretical foundation for self-organization of social-insect colonies, validated using data from four continents, which demonstrates that intraspecific competition between territorial animals can generate the large-scale hexagonal regularity of these patterns. However, this mechanism is not mutually exclusive with scale-dependent feedbacks. Using Namib Desert fairy circles as a case study, we present field data showing that these landscapes exhibit multi-scale patterning—previously undocumented in this system—that cannot be explained by either mechanism in isolation. These multi-scale patterns and other emergent properties, such as enhanced resistance to and recovery from drought, instead arise from dynamic interactions in our theoretical framework, which couples both mechanisms. The potentially global extent of animal-induced regularity in vegetation—which can modulate other patterning processes in functionally important ways—emphasizes the need to integrate multiple mechanisms of ecological self-organization.

Subcycle quantum electrodynamics 

Nature ( IF 38.138 ) 2017-01-18

C. Riek, P. Sulzer, M. Seeger, A. S. Moskalenko, G. Burkard, D. V. Seletskiy, A. Leitenstorfer 


Squeezed states of electromagnetic radiation have quantum fluctuations below those of the vacuum field. They offer a unique resource for quantum information systems and precision metrology, including gravitational wave detectors, which require unprecedented sensitivity. Since the first experiments on this non-classical form of light, quantum analysis has been based on homodyning techniques and photon correlation measurements. These methods currently function in the visible to near-infrared and microwave spectral ranges. They require a well-defined carrier frequency, and photons contained in a quantum state need to be absorbed or amplified. Quantum non-demolition experiments may be performed to avoid the influence of a measurement in one quadrature, but this procedure comes at the expense of increased uncertainty in another quadrature. Here we generate mid-infrared time-locked patterns of squeezed vacuum noise. After propagation through free space, the quantum fluctuations of the electric field are studied in the time domain using electro-optic sampling with few-femtosecond laser pulses. We directly compare the local noise amplitude to that of bare (that is, unperturbed) vacuum. Our nonlinear approach operates off resonance and, unlike homodyning or photon correlation techniques, without absorption or amplification of the field that is investigated. We find subcycle intervals with noise levels that are substantially less than the amplitude of the vacuum field. As a consequence, there are enhanced fluctuations in adjacent time intervals, owing to Heisenberg’s uncertainty principle, which indicate generation of highly correlated quantum radiation. Together with efforts in the far infrared, this work enables the study of elementary quantum dynamics of light and matter in an energy range at the boundary between vacuum and thermal background conditions.

Rational design of reconfigurable prismatic architected materials 

Nature ( IF 38.138 ) 2017-01-18

Johannes T. B. Overvelde, James C. Weaver, Chuck Hoberman, Katia Bertoldi 


Advances in fabrication technologies are enabling the production of architected materials with unprecedented properties. Most such materials are characterized by a fixed geometry, but in the design of some materials it is possible to incorporate internal mechanisms capable of reconfiguring their spatial architecture, and in

50 & 100 Years Ago 

Nature ( IF 38.138 ) 2017-01-18

 


50 Years AgoWhen spiders are given lysergic acid they construct webs of more than usual regularity; they become, like man in a similar situation, withdrawn from external stimuli so that their perceptive awareness is reduced, and they cease to adjust their webs to the

Reconfigurable materials: Algorithm for architectural origami 

Nature ( IF 38.138 ) 2017-01-18

Jamie Paik 


An algorithm has been developed allowing the rational design of origami-inspired materials that can be rearranged to change their properties. This might open the way to strategies for making reconfigurable robots. See Article p.347

Quantum optics: Quiet moments in time 

Nature ( IF 38.138 ) 2017-01-18

Marco Bellini 


'Squeezed' light exhibits smaller quantum fluctuations than no light at all. Localized squeezed regions have now been produced along an infrared light wave and probed with unprecedented time resolution. See Letter p.376

Cease and desist 

Nature ( IF 38.138 ) 2017-01-18

Tyler Young 


Our word is your bond.

Chemical and structural effects of base modifications in messenger RNA 

Nature ( IF 38.138 ) 2017-01-18

Emily M. Harcourt, Anna M. Kietrys, Eric T. Kool 


A growing number of nucleobase modifications in messenger RNA have been revealed through advances in detection and RNA sequencing. Although some of the biochemical pathways that involve modified bases have been identified, research into the world of RNA modification — the epitranscriptome — is still

Scaling single-cell genomics from phenomenology to mechanism 

Nature ( IF 38.138 ) 2017-01-18

Amos Tanay, Aviv Regev 


Three of the most fundamental questions in biology are how individual cells differentiate to form tissues, how tissues function in a coordinated and flexible fashion and which gene regulatory mechanisms support these processes. Single-cell genomics is opening up new ways to tackle these questions by

Elements of cancer immunity and the cancer–immune set point 

Nature ( IF 38.138 ) 2017-01-18

Daniel S. Chen, Ira Mellman 


Immunotherapy is proving to be an effective therapeutic approach in a variety of cancers. But despite the clinical success of antibodies against the immune regulators CTLA4 and PD-L1/PD-1, only a subset of people exhibit durable responses, suggesting that a broader view of cancer immunity is

From morphogen to morphogenesis and back 

Nature ( IF 38.138 ) 2017-01-18

Darren Gilmour, Martina Rembold, Maria Leptin 


A long-term aim of the life sciences is to understand how organismal shape is encoded by the genome. An important challenge is to identify mechanistic links between the genes that control cell-fate decisions and the cellular machines that generate shape, therefore closing the gap between

Tracing the peopling of the world through genomics 

Nature ( IF 38.138 ) 2017-01-18

Rasmus Nielsen, Joshua M. Akey, Mattias Jakobsson, Jonathan K. Pritchard, Sarah Tishkoff, Eske Willerslev 


Advances in the sequencing and the analysis of the genomes of both modern and ancient peoples have facilitated a number of breakthroughs in our understanding of human evolutionary history. These include the discovery of interbreeding between anatomically modern humans and extinct hominins; the development of

Frontiers in biology 

Nature ( IF 38.138 ) 2017-01-18

Orli Bahcall, Angela K. Eggleston, Nathalie Le Bot, Ursula Weiss 


The Nature Insight 'Frontiers in Biology' aims to cover timely and important developments across biology, ranging from molecular mechanisms to whole-organism physiology and biomedicine.Improvements in sequencing and in methods for enriching and extracting ancient DNA have furthered the temporal and geographic reach of

Turning point: Advocacy ambassador 

Nature ( IF 38.138 ) 2017-01-18

Virginia Gewin 


A social-media professional calls on researchers to speak out for their science.

Communication: Post-truth predicaments 

Nature ( IF 38.138 ) 2017-01-18

Virginia Gewin 


How can scientists get through to a public that's seemingly indifferent to objective facts?

John Glenn (1921–2016) 

Nature ( IF 38.138 ) 2017-01-18

William A. 'Bill' Anders 


US astronaut and senator.

Censorship: Beware scientists wielding red pens 

Nature ( IF 38.138 ) 2017-01-18

Bart Penders 


By inviting scientists to take their 'red pens to the Internet' and grade online sources of science reporting, Phil Williamson implies that science is the primary and final voice in public discussion (Nature540, 171;10.1038/540171a2016). This disregards other ways

Anthropocene: social science misconstrued 

Nature ( IF 38.138 ) 2017-01-18

Noel Castree 


Adding in a wider range of social-science expertise will not, in my view, help efforts to 'formalize the Anthropocene' as a geological age of human influence (E.Elliset al. Nature540, 192–193;10.1038/540192a2016). The authors rightly

Anthropocene: its stratigraphic basis 

Nature ( IF 38.138 ) 2017-01-18

Jan Zalasiewicz, Colin Waters, Martin J. Head 


As officers of the Anthropocene Working Group (AWG; J.Z. and C.W.) and chair of the Subcommission on Quaternary Stratigraphy (SQS; M.J.H.) of the International Commission on Stratigraphy (ICS), we note that the AWG has less power than Erle Ellis and colleagues imply (Nature540

Brussels Declaration: Twenty-point plan for science policy 

Nature ( IF 38.138 ) 2017-01-18

Michel Kazatchkine, Julian Kinderlerer, Aidan Gilligan 


The Brussels Declaration will be published at next month's meeting of the American Association for the Advancement of Science in Boston, Massachusetts. It is a 20-point blueprint for a set of ethics and principles to inform work at the boundaries of science, society and policy.

Books in brief 

Nature ( IF 38.138 ) 2017-01-18

Barbara Kiser 


Barbara Kiser reviews five of the week's best science picks.

Technology: He wrote the future 

Nature ( IF 38.138 ) 2017-01-18

Andrew Robinson 


On Arthur C. Clarke's centenary, Andrew Robinson lauds a prescient, original writer.

Space-weather forecast to improve with European satellite 

Nature ( IF 38.138 ) 2017-01-18

Elizabeth Gibney 


Probe could give early warnings of catastrophic solar storms heading for Earth.

Cancer reproducibility project releases first results 

Nature ( IF 38.138 ) 2017-01-18

Monya Baker, Elie Dolgin 


An open-science effort to replicate dozens of cancer-biology studies is off to a confusing start.

India’s first GM food crop held up by lawsuit 

Nature ( IF 38.138 ) 2017-01-18

Sanjay Kumar 


Scientists accused of deceiving the public about benefits of transgenic mustard.


The week in science: 13–19 January 2017.

Cancer biology: Tumours slowed by diet tweak 

Nature ( IF 38.138 ) 2017-01-18

 


A high-fat diet speeds tumour growth in mice, but this can be counteracted by drugs that lower levels of a metabolite in the blood.Diet can influence cancer survival, but the molecular reasons are largely unknown. Jing Chen at Emory University in Atlanta, Georgia, and

Conservation: Pristine forests are shrinking fast 

Nature ( IF 38.138 ) 2017-01-18

 


Less than one-quarter of the world's forests show no obvious signs of human activity, and the proportion of undisturbed forest has dropped markedly since the millennium.Peter Potapov at the University of Maryland in College Park and his co-workers used satellite images to identify areas

Evolution: How menopause emerged in whales 

Nature ( IF 38.138 ) 2017-01-18

 


Differences between the breeding success of mothers and daughters may have driven the evolution of menopause, according to a study on killer whales.Evolutionary biologists have long puzzled over why females of certain species — humans, killer whales and short-finned pilot whales — stop ovulating

Palaeontology: Trilobites laid eggs 

Nature ( IF 38.138 ) 2017-01-18

 


The discovery that extinct marine organisms called trilobites laid eggs provides the first direct evidence for how they reproduced.Trilobites lived between 520 million and 250 million years ago, and are one of the earliest known groups of arthropods (invertebrates, including modern insects, with exoskeletons

Ecology: Trees grow thick skin to survive fire 

Nature ( IF 38.138 ) 2017-01-18

 


Trees that live in fire-prone areas have evolved thick bark to protect themselves. This trait can be used as an indicator of how resilient a tree species is to increased fire risk under global warming.Adam Pellegrini, now at Stanford University in California, and his


Atmospheric methane and other short-lived greenhouse gases are set to keep the global sea level rising for several centuries — even after any potential decline or halt in emissions.Greenhouse gases in the atmosphere cause ocean warming and thermal expansion that results in sea-level rise.

Chemistry: Molecule gets knotted 

Nature ( IF 38.138 ) 2017-01-18

 


Scientists have braided a molecule into a knot with eight crossings, the most complex yet made in the lab.Flexible polymers can twist themselves into complex knots, but scientists have struggled to create all but the simplest structures. David Leigh and his colleagues at the

Neuroscience: How to turn on killer instinct 

Nature ( IF 38.138 ) 2017-01-18

 


The activation of a particular group of brain cells is all it takes to make mice hunt to kill.The brain's central amygdala has long been thought to have a role in producing emotions, particularly fear. To activate this brain region, Ivan de Araujo at


White rhinos can learn about each other by sniffing one another's faeces.Many mammals communicate through smells in their urine. To see whether faeces have a similar role, Courtney Marneweck at the University of KwaZulu-Natal in Pietermaritzburg, South Africa, and her colleagues analysed odours from

Base the social cost of carbon on the science 

Nature ( IF 38.138 ) 2017-01-18

 


The potential economic damage from global warming should not be influenced by politics.


They demonstrate the practice of science at its best.

Corrigendum: Structural basis of N6-adenosine methylation by the METTL3–METTL14 complex 

Nature ( IF 38.138 ) 2017-01-18

Xiang Wang, Jing Feng, Yuan Xue, Zeyuan Guan, Delin Zhang, Zhu Liu, Zhou Gong, Qiang Wang, Jinbo Huang, Chun Tang, Tingting Zou, Ping Yin 


Corrigendum: Structural basis of N6-adenosine methylation by the METTL3–METTL14 complex

Ultrafast nonthermal photo-magnetic recording in a transparent medium 

Nature ( IF 38.138 ) 2017-01-18

A. Stupakiewicz, K. Szerenos, D. Afanasiev, A. Kirilyuk, A. V. Kimel 


Discovering ways to control the magnetic state of media with the lowest possible production of heat and at the fastest possible speeds is important in the study of fundamental magnetism, with clear practical potential. In metals, it is possible to switch the magnetization between two stable states (and thus to record magnetic bits) using femtosecond circularly polarized laser pulses. However, the switching mechanisms in these materials are directly related to laser-induced heating close to the Curie temperature. Although several possible routes for achieving all-optical switching in magnetic dielectrics have been discussed, no recording has hitherto been demonstrated. Here we describe ultrafast all-optical photo-magnetic recording in transparent films of the dielectric cobalt-substituted garnet. A single linearly polarized femtosecond laser pulse resonantly pumps specific d−d transitions in the cobalt ions, breaking the degeneracy between metastable magnetic states. By changing the polarization of the laser pulse, we deterministically steer the net magnetization in the garnet, thus writing ‘0’ and ‘1’ magnetic bits at will. This mechanism outperforms existing alternatives in terms of the speed of the write–read magnetic recording event (less than 20 picoseconds) and the unprecedentedly low heat load (less than 6 joules per cubic centimetre).

Genomic deletion of malic enzyme 2 confers collateral lethality in pancreatic cancer 

Nature ( IF 38.138 ) 2017-01-18

Prasenjit Dey, Joelle Baddour, Florian Muller, Chia Chin Wu, Huamin Wang, Wen-Ting Liao, Zangdao Lan, Alina Chen, Tony Gutschner, Yaan Kang, Jason Fleming, Nikunj Satani, Di Zhao, Abhinav Achreja, Lifeng Yang, Jiyoon Lee, Edward Chang, Giannicola Genovese, Andrea Viale, Haoqiang Ying, Giulio Draetta, Anirban Maitra, Y. Alan Wang, Deepak Nagrath, Ronald A. DePinho 


The genome of pancreatic ductal adenocarcinoma (PDAC) frequently contains deletions of tumour suppressor gene loci, most notably SMAD4, which is homozygously deleted in nearly one-third of cases. As loss of neighbouring housekeeping genes can confer collateral lethality, we sought to determine whether loss of the metabolic gene malic enzyme 2 (ME2) in the SMAD4 locus would create cancer-specific metabolic vulnerability upon targeting of its paralogous isoform ME3. The mitochondrial malic enzymes (ME2 and ME3) are oxidative decarboxylases that catalyse the conversion of malate to pyruvate and are essential for NADPH regeneration and reactive oxygen species homeostasis. Here we show that ME3 depletion selectively kills ME2-null PDAC cells in a manner consistent with an essential function for ME3 in ME2-null cancer cells. Mechanistically, integrated metabolomic and molecular investigation of cells deficient in mitochondrial malic enzymes revealed diminished NADPH production and consequent high levels of reactive oxygen species. These changes activate AMP activated protein kinase (AMPK), which in turn directly suppresses sterol regulatory element-binding protein 1 (SREBP1)-directed transcription of its direct targets including the BCAT2 branched-chain amino acid transaminase 2) gene. BCAT2 catalyses the transfer of the amino group from branched-chain amino acids to α-ketoglutarate (α-KG) thereby regenerating glutamate, which functions in part to support de novo nucleotide synthesis. Thus, mitochondrial malic enzyme deficiency, which results in impaired NADPH production, provides a prime ‘collateral lethality’ therapeutic strategy for the treatment of a substantial fraction of patients diagnosed with this intractable disease.

Neurotoxic reactive astrocytes are induced by activated microglia 

Nature ( IF 38.138 ) 2017-01-18

Shane A. Liddelow, Kevin A. Guttenplan, Laura E. Clarke, Frederick C. Bennett, Christopher J. Bohlen, Lucas Schirmer, Mariko L. Bennett, Alexandra E. Münch, Won-Suk Chung, Todd C. Peterson, Daniel K. Wilton, Arnaud Frouin, Brooke A. Napier, Nikhil Panicker, Manoj Kumar, Marion S. Buckwalter, David H. Rowitch, Valina L. Dawson, Ted M. Dawson, Beth Stevens, Ben A. Barres 


A reactive astrocyte subtype termed A1 is induced after injury or disease of the central nervous system and subsequently promotes the death of neurons and oligodendrocytes.

Structure of a eukaryotic cyclic-nucleotide-gated channel 

Nature ( IF 38.138 ) 2017-01-18

Minghui Li, Xiaoyuan Zhou, Shu Wang, Ioannis Michailidis, Ye Gong, Deyuan Su, Huan Li, Xueming Li, Jian Yang 


The first high-resolution (3.5 Å) structure of a full-length cyclic-nucleotide-gated channel, revealing an unconventional, voltage-insensitive voltage-sensor domain and a unique coupling mechanism between cyclic-nucleotide-binding and pore-opening.

Communication between viruses guides lysis–lysogeny decisions 

Nature ( IF 38.138 ) 2017-01-18

Zohar Erez, Ida Steinberger-Levy, Maya Shamir, Shany Doron, Avigail Stokar-Avihail, Yoav Peleg, Sarah Melamed, Azita Leavitt, Alon Savidor, Shira Albeck, Gil Amitai, Rotem Sorek 


Some phages—viruses that infect bacteria—encode peptides that are secreted from infected cells and that, beyond a certain threshold, stimulate other viruses to switch from the lytic (killing the host cell) to lysogenic (dormant) phase.

IL-17 is a neuromodulator of Caenorhabditis elegans sensory responses 

Nature ( IF 38.138 ) 2017-01-18

Changchun Chen, Eisuke Itakura, Geoffrey M. Nelson, Ming Sheng, Patrick Laurent, Lorenz A. Fenk, Rebecca A. Butcher, Ramanujan S. Hegde, Mario de Bono 


Interleukin-17 functions as a neuromodulator in the roundworm Caenorhabditis elegans, acting directly on RMG hub interneurons to alter their response properties and contribution to behaviour.

Materials science: Versatile gel assembly on a chip 

Nature ( IF 38.138 ) 2017-01-18

Shoji Takeuchi 


Materials called hydrogels have potential applications as scaffolds for tissue engineering, but methods are needed to assemble them into complex structures that mimic those found in nature. Just such a method has now been reported.

Virology: Phages make a group decision 

Nature ( IF 38.138 ) 2017-01-18

Alan R. Davidson 


It emerges that phage viruses, which infect bacteria, use small peptides to communicate with each other. This observation of intercellular communication also reveals how viruses make a key developmental decision.

Cancer: Double trouble for tumours 

Nature ( IF 38.138 ) 2017-01-18

Giulia Biffi, David A. Tuveson 


When some cancer cells delete a tumour-suppressor gene, they also delete nearby genes. It emerges that one of these latter genes has a key metabolic role, revealing a therapeutic opportunity that might be relevant for many tumours.


Addendum: The rewards of restraint in the collective regulation of foraging by harvester ant colonies

Correction 

Nature ( IF 38.138 ) 2017-01-17

 


The Comment ‘Involve social scientists in defining the Anthropocene’ (E. Ellis et al. Nature540, 192–193; 2016) incorrectly stated that proposals for defining this epoch will be put forward for ratification by the International Geological Congress. In fact, they will be put to

How to turn competitors into collaborators 

Nature ( IF 38.138 ) 2017-01-17

Erica Ollmann Saphire, John M. Dye, Gary P. Kobinger, Larry Zeitlin, Kartik Chandran, Robert F. Garry 


Erica Ollmann Saphire and colleagues share lessons in finding treatments fast from the work on Ebola by the Viral Hemorrhagic Fever Immunotherapeutic Consortium.

Croatia’s science minister rejects calls to resign amid plagiarism scandal 

Nature ( IF 38.138 ) 2017-01-17

Mićo Tatalović, Nenad Jarić Dauenhauer 


Pavo Barišić says he won't step down after a parliamentary ethics committee found he copied another scholar's work.

Give the public the tools to trust scientists 

Nature ( IF 38.138 ) 2017-01-17

Anita Makri 


Anita Makri argues that the form of science communicated in popular media leaves the public vulnerable to false certainty.


Scientists must fight back with the truth about the debunked link between vaccines and autism.

The ligand Sas and its receptor PTP10D drive tumour-suppressive cell competition 

Nature ( IF 38.138 ) 2017-01-16

Masatoshi Yamamoto, Shizue Ohsawa, Kei Kunimasa, Tatsushi Igaki 


Normal epithelial cells often exert anti-tumour effects against nearby oncogenic cells. In the Drosophila imaginal epithelium, clones of oncogenic cells with loss-of-function mutations in the apico-basal polarity genes scribble or discs large are actively eliminated by cell competition when surrounded by wild-type cells. Although c-Jun N-terminal kinase (JNK) signalling plays a crucial role in this cell elimination, the initial event, which occurs at the interface between normal cells and polarity-deficient cells, has not previously been identified. Here, through a genetic screen in Drosophila, we identify the ligand Sas and the receptor-type tyrosine phosphatase PTP10D as the cell-surface ligand–receptor system that drives tumour-suppressive cell competition. At the interface between the wild-type ‘winner’ and the polarity-deficient ‘loser’ clones, winner cells relocalize Sas to the lateral cell surface, whereas loser cells relocalize PTP10D there. This leads to the trans-activation of Sas–PTP10D signalling in loser cells, which restrains EGFR signalling and thereby enables elevated JNK signalling in loser cells, triggering cell elimination. In the absence of Sas–PTP10D, elevated EGFR signalling in loser cells switches the role of JNK from pro-apoptotic to pro-proliferative by inactivating the Hippo pathway, thereby driving the overgrowth of polarity-deficient cells. These findings uncover the mechanism by which normal epithelial cells recognize oncogenic polarity-deficient neighbours to drive cell competition.

Evolutionary genomics of the cold-adapted diatom Fragilariopsis cylindrus 

Nature ( IF 38.138 ) 2017-01-16

Thomas Mock, Robert P. Otillar, Jan Strauss, Mark McMullan, Pirita Paajanen, Jeremy Schmutz, Asaf Salamov, Remo Sanges, Andrew Toseland, Ben J. Ward, Andrew E. Allen, Christopher L. Dupont, Stephan Frickenhaus, Florian Maumus, Alaguraj Veluchamy, Taoyang Wu, Kerrie W. Barry, Angela Falciatore, Maria I. Ferrante, Antonio E. Fortunato, Gernot Glöckner, Ansgar Gruber, Rachel Hipkin, Michael G. Janech, Peter G. Kroth, Florian Leese, Erika A. Lindquist, Barbara R. Lyon, Joel Martin, Christoph Mayer,  


The Southern Ocean houses a diverse and productive community of organisms. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus, based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean.

Compensatory water effects link yearly global land CO2 sink changes to temperature 

Nature ( IF 38.138 ) 2017-01-16

Martin Jung, Markus Reichstein, Christopher R. Schwalm, Chris Huntingford, Stephen Sitch, Anders Ahlström, Almut Arneth, Gustau Camps-Valls, Philippe Ciais, Pierre Friedlingstein, Fabian Gans, Kazuhito Ichii, Atul K. Jain, Etsushi Kato, Dario Papale, Ben Poulter, Botond Raduly, Christian Rödenbeck, Gianluca Tramontana, Nicolas Viovy, Ying-Ping Wang, Ulrich Weber, Sönke Zaehle, Ning Zeng 


Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

Gates Foundation research can’t be published in top journals 

Nature ( IF 38.138 ) 2017-01-13

Richard Van Noorden 


Publications such as Nature and Science have policies that clash with the global health charity's open-access mandate.

SEVEN DAYS 

Nature ( IF 38.138 ) 2017-01-12

 


The week in science: 6–12 January 2017

Five big mysteries about CRISPR’s origins 

Nature ( IF 38.138 ) 2017-01-12

Heidi Ledford 


Where did it come from? How do organisms use it without self-destructing? And what else can it do?

Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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