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This press release is copyright Nature.
VOL.470 NO.7334 DATED 17 FEBRUARY 2011
This press release contains:
Summaries of newsworthy papers:
Climate science: Human impact on flooding
Fossils: Ancient ‘seaweeds’ tell tales of the deep
Fossils: Avoiding the con of convergent evolution
Astronomy: A minimum mass for star-forming galaxies
Materials science: Bending the rules for transformation optics
Biology: The molecular mechanics of longevity
Astrophysics: Emission lines hold the key to black-hole masses
Stem cells: Driving the neural pathway
And finally… Pruning the tree of life
Mention of papers to be published at the same time with the same embargo
Geographical listing of authors
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[1] & [2] Climate science: Human impact on flooding (pp 378-385; N&V)
Anthropogenic greenhouse gases have significantly increased the probability of heavy precipitation and local flood risk, report two papers in Nature this week. The findings are among the first formal identifications of human contribution to extreme hydrological events.
It has previously been suggested that human-influenced global warming may be partly responsible for increases in heavy precipitation. However, because of the limited availability of daily observations, most studies to date have only examined the potential detectability of changes in precipitation through model–model comparisons. Francis Zwiers and colleagues studied rainfall from 1951 to 1999 in Northern Hemisphere land areas, including North America and Eurasia (including India). They show that human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found in approximately two-thirds of data-covered parts of Northern Hemisphere land areas.
In a separate study, Pardeep Pall and colleagues observed the UK floods of October and November 2000 — the wettest autumn in England and Wales since records began in 1766. They generated several thousand seasonal-forecast-resolution climate model simulations of autumn 2000, both under realistic conditions, and under conditions as they might have been had these greenhouse gas emissions and resulting large-scale warming never occurred. They found that in nine out of ten cases their model indicates that twentieth-century anthropogenic greenhouse gas emissions increased the risk of flooding in England and Wales by more than 20% and in two out of three cases by more than 90%.
Pall and colleagues stress that their work only relates to flood types similar to that of the UK in 2000; however, they suggest that their framework may provide a method for assessing how external factors may be affecting the likelihood of other event-types — including those that might have been made less likely by climate change, such as snow-melt floods.
CONTACT
Francis Zwiers (University of Victoria, Canada) Author paper [1]
Tel: +1 250 721 7223; E-mail: [email protected]
Xuebin Zhang (Environment Canada, Toronto, Canada) Co-author paper [1]
Tel: +1 416 739 4713 or tel: +1 416 274 5868; E-mail: [email protected]
Pardeep Pall (ETH Zurich, Switzerland) Author paper [2]
Tel: +41 44 632 33 64; E-mail: [email protected]
Myles Allen (University of Oxford, UK) Co-author paper [2]
Tel: +44 1865 272085 or tel: +44 7776 306691; E-mail: [email protected]
Richard Allan (University of Reading, UK) N&V author
Tel: +44 118 378 5568; E-mail: [email protected]
[3] Fossils: Ancient ‘seaweeds’ tell tales of the deep (pp 390-393; N&V)
The discovery of a diverse assemblage of fossilised, seaweed-like forms from approximately 600 million years ago is reported in Nature this week. The specimens, recovered from the Lantian Formation in South China, indicate that the morphological diversification of eukaryotes may have taken place much earlier than previously thought.
The deep-water Avalon biota, dating from around 579–565 million years (Myr) ago, is often regarded as the earliest known fossil assemblage of macroscopic, complex life forms. Xunlai Yuan and colleagues describe fossils from the early Ediacaran Lantian Formation, which predate the Avalon biota but which show a comparable degree of diversity and complexity. The Lantian fossils were preserved in the carbonaceous black shales on the sea floor and date from around 600 Myr ago — a time when the Earth had only just recovered from the Marinoan glaciation. The centimetre-scale fossils fall into five morphological types, possibly representing around 15 species. Some resemble some modern algae, such as the kelp Postelsia palmaeformis, while others have no modern equivalents.
It is thought the oxygenation of the deep oceans during the mid-Ediacaran triggered the rise of the Avalon biota. In the paper, Yuan and his team report that the redox history of the Ediacaran oceans may in fact have been more complicated; further geochemical, palaeontological and sedimentological analyses are needed to fully understand these complexities.
CONTACT
Xunlai Yuan (Nanjing Institute of Geology and Palaeontology, China)
Tel: +86 25 8328 2217; E-mail: [email protected]
Guy Narbonne (Queen's University, Kingston, Canada) N&V author
Tel: +1 613 533 6168; E-mail: [email protected]
[4] Fossils: Avoiding the con of convergent evolution (pp 347-352)
Convergent evolution is so pervasive in the hominin family tree that interpreting certain fossils as representatives of early humans may not be as straightforward as previously thought, suggests a Review in this week’s Nature.
The researchers who analysed the fossil evidence for Ardipithecus ramidus, a 4.4 million-year-old hominid from Ethiopia, say it is an early human species, mainly due to its bipedality and the morphology of its canines. However, Bernard Wood and Terry Harrison argue that the presence of homoplasy — convergent evolution that leads to the same biological trait appearing in unrelated species — throughout hominin history can lead to certain species being incorrectly classified as hominins.
Fossil evidence provides critical evidence about the early stages of human evolution, but Wood and Harrison suggest that palaeoanthropologists need to acknowledge the limitations of their fossil evidence when generating hypotheses about the relationships among our ancestors. For example, phylogenetic analyses that work for large taxonomic units may be less effective when applied to closely related taxa. New imaging techniques and methods that allow non-destructive access to the microstructure of fossils should help researchers to discriminate between different phylogenetic analyses of these taxa and make more accurate classifications.
CONTACT
Bernard Wood (George Washington University, Washington, DC, USA)
Tel: +1 202 994 6077; E-mail: [email protected]
[5] Astronomy: A minimum mass for star-forming galaxies (AOP)
DOI: 10.1038/nature09771
***This paper will be published electronically on Nature's website on 16 February at 1800 London time / 1300 US Eastern Time as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 February, but at a later date. ***
The ‘haloes’ of dark matter that surround the Universe’s most active star-forming galaxies are each more massive than about 300 billion solar masses, according to observations reported online this week in Nature. This finding supports the idea of a minimum mass scale for efficient star formation, and will help to constrain theoretical models of galaxy formation and evolution.
The extragalactic far-infrared background radiation comes from optically faint, dusty galaxies in which new stars are forming. These galaxies are expected to trace the large-scale structure of the Universe, especially in models that link galaxy formation and evolution to the distribution of dark matter. Although these faint, ‘submillimetre’ galaxies are challenging to study individually, their average properties can be inferred from the statistical properties of the background radiation.
Asantha Cooray and colleagues note that any clustering of the submillimetre galaxies is expected to leave a distinct signature in the spatial intensity variations of the background radiation. Using new data from the Herschel Space Observatory, the authors measure the angular power spectrum of these intensity variations, which reveals strong clustering. Assuming that this clustering reflects the underlying distribution of dark matter, and fitting the data to a halo model of galaxy formation, the authors derive an estimate of about 300 billion solar masses for the minimum halo mass.
CONTACT
Asantha Cooray (University of California, Irvine, CA, USA)
Tel: +1 949 824 6832; E-mail: [email protected]
[6] Materials science: Bending the rules for transformation optics (pp 369-373; N&V)
Scientists have produced an artificial material with an extremely high refractive index, which might have applications in high-resolution imaging. The metamaterial, described in Nature this week, achieves electromagnetic properties that are not attainable with natural materials.
Producing materials with an unnaturally high refractive index is of great value for the development of novel transformation optics (tools that use electromagnetic waves to control light). Bumki Min and colleagues have created a broadband, flexible terahertz metamaterial with a refractive index of 38.6. Naturally occurring materials typically have an optical refractive index of between one and three.
The unusually high index of refraction demonstrated by the metamaterial could greatly extend light-manipulating capabilities, and may also be of use in cloaking devices.
CONTACT
Bumki Min (Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea)
Tel: +82 42 350 3234; E-mail: [email protected]
Xiang Zhang (University of California, Berkeley, CA, USA) N&V author
Tel: +1 510 643 4978; E-mail: [email protected]
[7] Biology: The molecular mechanics of longevity (pp 404-408)
A newly discovered signalling pathway that helps regulate energy homeostasis in worms has profound effects on longevity, a Nature paper reveals.
It is already known that nematode lifespan can be increased by altering the levels of two different proteins, AMPK and calcineurin, but the related molecular pathways have remained unclear. Andrew Dillin and colleagues show that the worm protein CRTC-1 has a pivotal role in these life-extending effects.
CRTC-1 is the only worm member in the family of CREB-regulated transcriptional co-activators, or CRTCs. And, like mammalian family members, CRTC-1 interacts with a worm version of the CREB transcription factor (CRH-1). Reducing crtc-1 or crh-1 levels increases lifespan, the team show. Down-regulating components of the CRTC/CREB pathway is known to yield health benefits for mice, so it will be interesting to see if the same applies to humans.
CONTACT
Andrew Dillin (Salk Institute for Biological Studies, La Jolla, CA, USA)
Tel: +1 858 453 4100, ext. 1099; E-mail: [email protected]
[8] Astrophysics: Emission lines hold the key to black-hole masses (pp 366-368)
The mysterious central regions of active galaxies are giving up some of their secrets, thanks to an ingenious new way of probing these regions. In this week’s Nature, Wolfram Kollatschny and Matthias Zetzl show that the shapes of emission lines in the spectra of active galactic nuclei provide important constraints on the gas velocities in their central accretion disks, providing more accurate estimates for the masses of the resident black holes.
Super-massive black holes at the centres of active galaxies are surrounded by extremely luminous, compact regions thought to be associated with accretion disks of material falling into the black hole. These regions are too small to be spatially resolved, leaving their structure and kinematics largely unknown, despite decades of intensive study.
Examining archival spectra for a sample of 37 active galactic nuclei, Kollatschny and Zetzl uncovered a systematic variation in the shapes of several emission lines, from which they were able to infer that the predominant gas motion in the central regions is orbital rotation, combined with turbulence. From the rotation velocities, the authors were able to derive the central black-hole masses, which are two to ten times smaller than previous estimates.
CONTACT
Wolfram Kollatschny (University of Göttingen, Germany)
Tel: +49 551 395 065; E-mail: [email protected]
[9] Stem cells: Driving the neural pathway (AOP)
DOI: 10.1038/nature09726
***This paper will be published electronically on Nature's website on 16 February at 1800 London time / 1300 US Eastern Time as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 February, but at a later date. ***
A protein that drives the intrinsic conversion of embryonic stem (ES) cells into neural cells is revealed in this week’s Nature.
Embryonic stem cells can turn into any of the many different cell types in the body, yet in culture, their default pathway is to differentiate into neural cells. Yoshiki Sasai and colleagues demonstrate that the nuclear protein Zfp521 is necessary and sufficient to promote this conversion — the protein triggers neural differentiation even when cells are cultured with differentiation-blocking molecules, and Zfp521-depleted ES cells do not differentiate into neural cells.
Zfp521 belongs to the family of zinc-finger nuclear proteins, molecules that bind to specific DNA sequences to switch genes on and off. This study highlights the importance of Zfp521 as a cell-intrinsic factor driving ES cell fate, advancing our understanding of mammalian development and with implications for regenerative medicine and drug discovery.
CONTACT
Yoshiki Sasai (RIKEN Center for Developmental Biology, Kobe, Japan)
Tel: +81 78 306 1841; E-mail: [email protected]
[10] And finally… Pruning the tree of life (AOP)
DOI: 10.1038/nature09705
***This paper will be published electronically on Nature's website on 16 February at 1800 London time / 1300 US Eastern Time as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 February, but at a later date. ***
Climate change is likely to thin the European tree of life but without loss of overall diversity, indicates a modelling study in this week’s Nature. The paper, which focuses on phylogenetic diversity, suggests a less drastic loss than previous modelling studies, which have focused on taxonomic diversity.
Phylogenetic diversity focuses on the evolutionary relatedness of species. Wilfried Thuiller and colleagues projected the impact of climate change on the phylogenetic diversity of European plants, birds and mammals. Although some ‘branches’ seem more vulnerable than others, the overall effect is a thinning of tree without a large drop in total biodiversity.
Northern and Southern European species are, however, predicted to respond differently — reductions in phylogenetic diversity will be greater in Southern Europe, and gains are expected in high latitude and altitude regions — so biodiversity is expected to become more uniform across the continent.
CONTACT
Wilfried Thuiller (Université Joseph Fourier, Grenoble, France)
Tel: +33 476 51 44 97; E-mail: [email protected]
ALSO IN THIS ISSUE…
[11] Asymmetric cell divisions promote Notch-dependent epidermal differentiation (pp 353-358)
[12] Tbx6-dependent Sox2 regulation determines neural or mesodermal fate in axial stem cells (pp 394-398)
[13] The novel gene twenty-four defines a critical translational step in the Drosophila clock (pp 399-403)
[14] CKI-alpha ablation highlights a critical role for p53 in invasiveness control (pp 409-413)
[15] Coronin 2Amediates actin-dependent de-repression of inflammatory response genes (pp 414-418)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 16 February at 1800 London time / 1300 US Eastern Time as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 February, but at a later date. ***
[16] Tumour-infiltrating regulatory T cells stimulate mammary cancer metastasis through RANKL RANK signalling
DOI: 10.1038/nature09707
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
CANADA
Lethbridge: 5
Toronto: 1
Vancouver: 5
Victoria: 1
CHINA
Nanjing: 3
Xi’an: 3
FINLAND
Helsinki: 14
FRANCE
Didcot: 5
Gif-sur-Yvette: 5
Grenoble: 10
Marseille: 5
Orsay: 5
Paris: 5
GERMANY
Göttingen: 8
Munich: 5
ISRAEL
Jerusalem: 14
Rehovot: 14
ITALY
Milan: 15
Padua: 5
JAPAN
Kobe: 9
Kyoto: 9
Osaka: 12
Tsukuba: 2
PORTUGAL
Évora: 10
REPUBLIC OF KOREA
Daejeon: 6, 13
Pohang: 13
Seoul: 6
SPAIN
Madrid: 5, 10
Tenerife: 5
SWITZERLAND
Zurich: 2
UNITED KINGDOM
Brighton: 5
Cardiff: 5
Dorking: 5
Edinburgh: 1, 5
Exeter: 2
Hatfield: 5
London: 2, 5, 12
Manchester: 5
Oxford: 2
UNITED STATES OF AMERICA
California
Irvine: 5
La Jolla: 7, 15, 16
Pasadena: 5
San Diego: 16
Colorado
Boulder: 5
District of Columbia
Washington: 4
Florida
Tampa: 16
Illinois
Evanston: 13
Maryland
Greenbelt: 5
Massachusetts
Waltham: 15
Worcester: 15
New York
New York: 4, 11, 12
Virginia
Blacksburg: 3
PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: [email protected]
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