This press release contains:
· Summaries of newsworthy papers:
Social evolution: ‘Til kingdom come
Astronomy: Cold gas feeding distant galaxies
Neuroscience: Formation of the blood–brain barrier
Biology: Feast, famine and the evolution of sex
Environmental science: Organic aerosols firm up
Virology: Herpes simplex virus ‘entry’ protein
And finally… When is a comet not a comet?
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Social evolution: ‘Til kingdom come (pp 801-804; N&V)
The evolution of political complexity in society, like biological evolution, tends to proceed through a series of small steps, according to a study published in this week’s Nature.
There has been much debate as to whether human political complexity has evolved through small stages — from tribes to chiefdoms to states — or through larger, non-sequential increases. Although archaeological and ethnic data support the former model, there has been an absence of rigorous, quantitative testing.
Thomas Currie and colleagues evaluate six competing models of political evolution in 84 Austronesian-speaking societies using phylogenetic methods — some models reflect traditional social evolutionary theories, where political complexity increases in small, hierarchical steps, and others allow larger, non-sequential steps. In the models that best fit the data, political complexity rises in a series of small steps — in Hawaii in the early 1800s, for example, states were formed when dominant chiefdoms conquered neighbouring chiefdoms. Larger steps are also possible when complexity falls.
The study suggests that the same kinds of technique used to study complex biological systems can be used to investigate long-term human social and cultural evolution.
Author contact
Thomas Currie (University College London, UK)
Tel: +44 20 7679 8781
E-mail: [email protected]
Jared Diamond (University of California, Los Angeles, CA, USA) N&V author
Tel: +1 310 825 6177
E-mail: [email protected]
[2] Astronomy: Cold gas feeding distant galaxies (p 811-813)
A recently proposed mechanism for the growth of galaxies in the early Universe receives support this week from observations published in Nature. Giovanni Cresci and colleagues present chemical abundance maps for three distant galaxies that provide evidence for the funnelling of cold, primordial gas to the galaxies’ central, star-forming regions.
Massive galaxies in the early Universe formed stars at very high rates. It has recently been suggested that this activity could have been fed by streams of cold gas with an essentially primordial composition, low in elements heavier than helium. If this ‘metal-poor’ gas is funnelled to a galaxy’s central, star-forming region, it will leave an observable signature, in the form of reduced metallicity in the galaxy’s central gas, as compared with the gas further out. This is the inverse of the pattern seen in nearby, younger galaxies.
Cresci and colleagues used near-infrared spectroscopy to map the abundances of several elements in three galaxies at redshifts greater than 3 — corresponding to a time, more than 11 billion years ago, when star formation was proceeding with great intensity. In all three galaxies, the authors find the inverse metallicity gradient that would be expected from the accretion and funnelling of primordial gas. This suggests that, at least for the type of galaxy studied, the accretion of metal-poor gas is a common feature of early galaxy growth.
Author contact
Giovanni Cresci (INAF - Arcetri Astrophysical Observatory, Florence, Italy)
Tel: +39 055 2752 230
E-mail: [email protected]
[3] & [4] Neuroscience: Formation of the blood–brain barrier (AOP)
DOI: 10.1038/nature09513
DOI: 10.1038/nature09522
***These papers will be published electronically on Nature's website on 13 October at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 14 October, but at a later date. ***
Blood-vessel-surrounding cells called pericytes have a key role in the development of the blood–brain barrier (BBB), two Nature papers suggest.
The BBB is a physical barrier made up of vascular endothelial cells that restricts the movement of molecules and ions between blood and brain. It had been thought that the structure develops postnatally as non-neuronal cells called astrocytes signal to endothelial cells. But Richard Daneman and colleagues show that the BBB develops during embryogenesis, long before astrocytes are formed, and that pericytes have a critical role.
The importance of pericytes is supported in a second study, by Christer Betsholtz and colleagues, showing that adult mice lacking pericytes have a leaky BBB. So, pericyte-deficient animal models should aid our understanding of BBB formation and disease, and the development of molecules that can regulate the barrier.
Author contact
Richard Daneman (University of California, San Francisco, CA, USA) Author paper [3]
Tel: +1 415 476 3658
E-mail: [email protected]
Christer Betsholtz (Karolinska Institute, Stockholm, Sweden) Author paper [4]
Tel: +46 8 5248 7960
E-mail: [email protected]
[5] Biology: Feast, famine and the evolution of sex (AOP)
DOI: 10.1038/nature09449
***This paper will be published electronically on Nature's website on 13 October at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) 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 14 October, but at a later date. ***
Sex is more likely to evolve in spatially heterogeneous habitats, a study of rotifers published in this week’s Nature suggests.
Rotifers are tiny water-dwelling animals that can switch between sexual and asexual reproduction. Lutz Becks and Aneil Agrawal studied the effect of environment on reproductive mode, and found that sexual reproduction was most likely to evolve in varied habitats that included spatially distinct areas of low- and high-quality food. Homogeneous environments, where food quality did not vary across habitat, did not favour sexual evolution.
Direct experimental tests of the conditions under which sex evolves have been rare, and this study is one of the first to demonstrate the evolution of sex within a population. The data also suggest that the higher level of sex observed under heterogeneous conditions is not due to sex being less costly or selection against sex being less efficient; rather, sex is sufficiently advantageous in these circumstances to overwhelm its inherent costs.
Author contact
Lutz Becks (University of Toronto, Canada)
Tel: +1 416 948 2086
E-mail: [email protected]
[6] Environmental science: Organic aerosols firm up (pp 824-827; N&V)
Atmospheric aerosol particles that have long been assumed to be liquid can in fact be amorphous solids, according to work published in this week’s Nature. This finding will require substantial rethinking of the chemical and physical processes involving these particles, and their implications for air quality and climate.
Organic aerosol particles are found throughout the atmosphere. Secondary organic aerosol (SOA) particles form by the oxidation of volatile organic compounds, most of which come from plants. SOA particles influence the Earth’s climate by scattering solar radiation and acting as nuclei for cloud formation. Models of the formation and behaviour of these particles have assumed that they are liquid, but recent laboratory experiments have suggested that they might be in an amorphous solid state.
Annele Virtanen and colleagues now present direct evidence, obtained in both plant chambers and a northern forest, that plant-derived SOA particles exist as amorphous solids. The atmospheric processes that will have to be re-examined include the partitioning of organic compounds between air and particles, the ability of SOA particles to absorb moisture (with implications for cloud formation), and the rates of chemical reactions— all of which affect the atmospheric lifetime of the particles, and of the compounds they contain.
Author contact
Annele Virtanen (Tampere University of Technology, Finland)
Tel: +358 40 1981002
E-mail: [email protected]
Paul Ziemann (University of California, Riverside, CA, USA) N&V author
Tel: +1 951 827 5127
E-mail: [email protected]
[7] Virology: Herpes simplex virus ‘entry’ protein (pp 859-862)
A newly identified entry receptor may help the herpes simplex virus-1 (HSV-1) enter host cells. The find, reported in this week’s Nature, should aid the development of improved therapeutics for this clinically important pathogen.
The receptor, non-muscle myosin heavy chain IIA (NMHC-IIA), interacts with a particular protein found on the surface of the virus, Yasushi Kawaguchi and colleagues demonstrate. They show that treatment with an NMHC-IIA inhibitor reduces HSV-1 infection in cell culture and a mouse model.
Author contact
Yasushi Kawaguchi (University of Tokyo, Japan)
Tel: +81 3 6409 2070
E-mail: [email protected]
[8] & [9] And finally… When is a comet not a comet? (pp 814-819; N&V)
A collision in the asteroid belt has been observed (rather than inferred to have happened) in 'recent' history for the first time. The finding is discussed in two papers in Nature this week.
When P/2010 A2 was discovered, complete with tail, in January 2010 it was designated as a comet. But its ‘headless’ appearance and orbit in the inner reaches of the main asteroid belt were most un-comet-like, prompting suggestions that that it was an asteroid with a tail, rather than a member of the recently recognized class of main-belt comets.
Colin Snodgrass and colleagues observed P/2010 A2 from the Rosetta spacecraft, which was approaching the asteroid belt for its fly-by of the asteroid Lutetia. They conclude that the object’s tail is made up of debris from an asteroid collision — and use computer modelling to date the collision to February 2009. David Jewitt and team took high-resolution images with the Hubble Space Telescope between January and May 2010 and estimate a 120-metre diameter for the object’s ‘nucleus’, with millimetre-sized dust particles forming the tail. Both teams trace the collision back to early 2009.
Author contact
Colin Snodgrass (Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany) Author paper [8]
Tel: +49 5556 979 358
E-mail: [email protected]
David Jewitt (University of California, Los Angeles, CA, USA) Author paper [9]
Tel: +1 310 825 2521
E-mail: [email protected]
David Nesvorný (Southwest Research Institute, Boulder, CO, USA) N&V author
Tel: +1 303 546 0023
E-mail: [email protected]
ALSO IN THIS ISSUE…
[10] The Ndc80 kinetochore complex forms oligomeric arrays along microtubules (pp 805-810)
[11] xnd-1 regulates the global recombination landscape in Caenorhabditis elegans (pp 839-843)
[12] The structural basis for autonomous dimerization of the pre-T-cell antigen receptor (pp 844-848; N&V)
[13] Anthrax toxins cooperatively inhibit endocytic recycling by the Rab11/Sec15 exocyst (pp 854-858)
[14] Pannexin 1 channelsmediate ‘find-me’ signal release and membrane permeability during apoptosis (pp 863-867)
[15] The proteasome antechamber maintains substrates in an unfolded state (pp 868-871)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 13 October at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 14 October, but at a later date. ***
[16] Single-molecule analysis of Mss116-mediated group II intron folding
DOI: 10.1038/nature09422
[17] Satellite phage TLC-phi enables toxigenic conversion by CTX phage through dif site alteration
DOI: 10.1038/nature09469
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.
AUSTRALIA
Clayton: 12
Parkville: 12
St Lucia: 12
BANGLADESH
Dhaka: 17
CANADA
Burnaby: 11
London: 14
Toronto: 5, 15
CHILE
Santiago: 8
FINLAND
Helsinki: 6
Kuopio: 6
Tampere: 6
FRANCE
Marseille: 8
Meudon: 8
GERMANY
Bielefeld: 6
Cologne: 5
Garching: 2
Heidelberg: 4
Katlenburg-Lindau: 8
Mainz: 6
Martinsried: 15
ITALY
Catone: 2
Florence: 2
Milan: 10
Padua: 8
JAPAN
Osaka: 7
Saitama: 7
Tokyo: 1, 7
NETHERLANDS
Noordwijk: 8, 9
NEW ZEALAND
Auckland: 1
POLAND
Warsaw: 8
SPAIN
Granada: 8
SWEDEN
Gothenburg: 4
Mölndal: 4
Stockholm: 4,
Uppsala: 4,
UNITED KINGDOM
Belfast: 8
Canterbury: 8
London: 1
UNITED STATES OF AMERICA
California
Berkeley: 10
La Jolla: 13, 14
Los Angeles: 9
Pasadena: 8
San Francisco: 3
Stanford: 3
Connecticut
New Haven: 16
Maryland
Baltimore: 9, 11
Laurel: 9
Massachusetts
Billerica:
Boston: 17
Waltham: 10
Michigan
Detroit: 16
North Carolina
Chapel Hill: 14
Pennsylvania
Pittsburgh: 11
Texas
Fort Worth: 13
Virginia
Charlottesville: 14
Wisconsin
Madison: 7
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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