Tectonics: Full speed ahead

Summaries of newsworthy papers include Life’s a beach, Genes tell our evolutionary tale, The shadowy genome, Biggest black hole has even bigger companion, Rise and shine, Gene essential to sperm production identified, Old trick, new dog, A sunny outlook for nanowires and Sex determination linked to fitness

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This press release is copyright Nature.

VOL.449 NO.7164 DATED 18 OCTOBER 2007

This press release contains:

· Summaries of newsworthy papers:

Tectonics: Full speed ahead

Human evolution: Life’s a beach

Human genetics: Genes tell our evolutionary tale

Commentary: The shadowy genome

Astrophysics: Biggest black hole has even bigger companion

Neuropsychiatry: Rise and shine

Genetics: Gene essential to sperm production identified

Immunology: Old trick, new dog

Nanotechnology: A sunny outlook for nanowires

And finally: Sex determination linked to fitness

· Mention of papers to be published at the same time with the same embargo

· Geographical listing of authors

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[1] Tectonics: Full speed ahead (pp 894-897; N&V)

The thinning of the Indian tectonic plate may be responsible for the great speed at which it moved in the past, suggests a paper in Nature this week. The observation that the Indian continental plate is thinner than other fragments of the Gondwanaland supercontinent could explain why India travelled so fast after it broke away from Africa and Australia and eventually crashed into Asia to form the Himalayas and Tibetan plateau.

The Indian tectonic plate has been on a fast-track collision course with Asia since the breakup of the Gondwanaland supercontinent 140 million years ago. This break-up produced Africa, Australia, Antarctica and India, creating the Indian Ocean between them. Plate reconstructions show that the Indian plate moved very fast throughout the Cretaceous period — slowing down only after its collision with Asia 50 million years ago. The Australian and African plates moved little distance in this time, while Antarctica remained nearly stationary.

Rainer Kind and colleagues used seismic body-wave observations to detect the lower boundary of the plates that came from Gondwanaland. They found that as well as moving much faster than the other fragments, the Indian plate is also surprisingly thin — unusual for a piece of old, stable continental crust. They found that the crustal or lithospheric roots in South Africa, Australia and Antarctica are between 180 and 300 kilometres deep; but the Indian lithosphere only reaches about 100 kilometres. The authors propose that the plume from the mantle that is thought to have broken up Gondwanaland may also have melted the lower half of the Indian lithosphere, thinning it and thus enabling it to accelerate.

CONTACT

Rainer Kind (GeoForschungsZentrum Potsdam, Germany)

Tel: +49 331 288 1240; [email protected]

Dietmar Müller (University of Sydney, Australia) N&V author

Tel: +61 41 866 7553; E-mail: [email protected]

[2] Human evolution: Life’s a beach (pp 905-908; N&V)

One of the first things that modern humans did when they evolved was head for the beach! This is illustrated in dramatic fashion by researchers who present evidence of shellfish use and coastal occupation in a study in this week’s Nature.

The earliest previous evidence for human use of marine resources and coastal habitats was dated to around 125,000 years ago. Curtis Marean and colleagues now report that the exploitation of coastal resources by Homo sapiens may have occurred significantly earlier, around 164,000 years ago. The team reveal their findings from a sea cave on the coast of South Africa, which suggest that our early ancestors expanded their diet to include shellfish and adopted cultural processes including the use of the pigment red ochre.

The authors propose that these adaptations to coastal life may have been critical to survival at a time when the world was going through a cool, dry spell and Africa was mostly desert — harsh conditions that probably drove small bands of hunter-gatherers towards the sea.

CONTACT

Curtis Marean (Arizona State University, Tempe, AZ, USA)

Tel: +1 480 965 7796; E-mail: [email protected]

Sally McBrearty (University of Connecticut, Storrs, CT, USA) N&V author

Tel: +1 860 486 2857; E-mail: [email protected]

Chris Stringer (Natural History Museum, London, UK) N&V author

Tel: +44 20 7942 5539; E-mail: [email protected]

[3] & [4] Human genetics: Genes tell our evolutionary tale (pp 913-918, 851-861)

Geneticists have identified a number of genes, for a variety of functions, that show the hallmarks of having been favoured by natural selection in different populations. The researchers identify two genes in a Nigerian population that show evidence of having been shaped by evolution. They also find similar hallmarks in two genes involved in skin pigmentation in people of European ancestry, and two genes involved in hair-follicle development in Asians.

The search, carried out by Pardis Sabeti and colleagues and described in this week's Nature, aimed to spot regions of minimal genetic variation within populations — evidence that the gene sequence in question was preserved by the effects of natural selection within that population. In compiling their results, the researchers took advantage of new data from the International HapMap Project, a vast catalogue of human genetic variations that should help to pinpoint the genetic hallmarks of many diseases. These new HapMap data, generated by an international consortium of researchers behind the project, are also published in this week's Nature.

The consortium’s results add details of 2.1 million newly described points in the genome where the genetic code varies by just a single letter from person to person, bringing the overall tally of mutations documented by the project to well over 3 million. The project uses genetic samples from 270 people, from Nigeria, Utah, China and Japan.

CONTACT

Pardis Sabeti (Broad Institute, Cambridge, MA, USA) Author paper [3]

Tel: +1 617 252 1190; E-mail: [email protected]

Gilean McVean (University of Cambridge, UK) Author paper [4]

Tel: +44 1223 333 992; E-mail: [email protected]

Commentary: The shadowy genome

Can personal genomics live up to the hype, asks a commentary in Nature this week. The fully sequenced genomes of James Watson and Craig Venter elicit headlines but reveal little of consequence. Steven Brenner asks: If the genome is so revealing, why was so little revealed?

Indeed, says Brenner, it remains to be seen whether we will learn anything more important from our genomes than the need to use more sunscreen, eat better, and exercise more. Yet, he argues that the genetics community needs to start building a public resource — a Genome Commons — for describing human genetic variation and its consequences. By consolidating everything we know about genome variation in a public knowledge base, Brenner believes we can eventually make productive use of personal genetic information.

CONTACT

Steven Brenner (University of California, Berkeley, CA, USA)

Tel: +1 510 643 9131; E-mail: [email protected]

[5] Astrophysics: Biggest black hole has even bigger companion (pp 872-875; N&V)

The most massive stellar black hole discovered in orbit with a companion star is reported in this week’s Nature, with a mass 16 times that of our Sun. The find is all the more remarkable because models to explain such black holes’ formation from massive stars have difficulty producing anything greater than ten solar masses.

Jerome A. Orosz and colleagues found the black hole and its companion in the spiral galaxy Messier 33. The companion star passes directly in front of the black hole on its three-day orbit, eclipsing the black hole’s X-ray emission. This allowed the team to calculate the pair’s masses more accurately than usual. The companion star is also the most massive known in an X-ray binary, weighing in at 70 solar masses. This distant binary represents an important system in the study of high mass stellar black holes and X-ray binaries.

CONTACT

Jerome A. Orosz (San Diego State University, San Diego, CA, USA)

Tel: +1 619 594 7118; E-mail: [email protected]

Tomasz Bulik (The University of Warsaw, Poland) N&V author

Tel: +48 225 530 507 Ex114; E-mail: [email protected]

[6] Neuropsychiatry: Rise and shine (AOP)

DOI: 10.1038/nature06310

***This paper will be published electronically on Nature's website on 17 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 18 October, but at a later date.***

Researchers have established a causal link between the activity of a particular group of brain cells and transitions between sleep and wakefulness. Luis de Lecea and colleagues report their findings in this week’s issue of Nature.

Hypocretin-producing neurons (Hcrt neurons) are located in a region known as the lateral hypothalamus, and are active during transitions from sleep to waking states. They are important for arousal stability, as their loss is linked to narcolepsy, a debilitating sleep disorder. Here the authors directly probe the impact of Hcrt neuron activity on the sleep state of mice, using optical stimulation to target Hcrt neurons genetically engineered to respond to light. They found that stimulating these cells increased the likelihood of transition from either slow wave sleep or rapid eye movement sleep to wakefulness, with higher frequencies reducing the length of time between the end of light stimulation and waking.

This is the first time that a direct link between the activity of Hcrt neurons and sleep-to-wake transitions has been confirmed. The authors suggest that because Hcrt deficiency results in arousal instability associated with narcolepsy, further insights into sleep disorders may result from their findings.

CONTACT

Luis de Lecea (Stanford University, Palo Alto, CA, USA)

Tel: +1 650 736 9039; E-mail: [email protected]

[7] Genetics: Gene essential to sperm production identified (AOP)

DOI: 10.1038/nature06236

***This paper will be published electronically on Nature's website on 17 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 18 October, but at a later date.***

In a study published online this week in Nature, researchers report the identification of a gene that has a key role in the development of sperm. Yi Zhang and colleagues propose that Jhdm2a — a histone demethylase gene — might even be a new candidate gene involved in some infertility syndromes.

The authors examine the function of JHDM2A in mice using a number of techniques. By analysing the levels of the JHDM2A protein, they find that it is highly expressed in the testis, with levels increasing during spermatogenesis. To explore further its role during the late stages of male germ-cell development, Zhang and colleagues also studied the effects of disrupting the Jhdm2a gene. Mutant mice have smaller testes, a lower sperm count and are infertile. Of the few mature sperm recovered from mutant mice, all had abnormally shaped heads are most were immotile.

These findings highlight the critical role of JHDM2A in the late stages of sperm production and maturation. Further work is needed to determine whether the human equivalent of this gene is involved in infertility.

CONTACT

Yi Zhang (University of North Carolina, Chapel Hill, NC, USA)
Tel: +1 919 843 8225; E-mail: [email protected]

[8] Immunology: Old trick, new dog (pp 919-922)

A new model of anti-viral response in mammals is presented in Nature this week. The research demonstrates that microRNAs (miRNAs), activated by interferon, can help fight hepatitis C in mammals, showing for the first time that they are active in mammalian virus responses.

Scientists know that plants and invertebrates use RNA silencing, through miRNAs, in the battle against viral infection. Here Michael David and colleagues show that eight miRNAs, rapidly encouraged into action by interferon (IFN)-beta, have specific targets within the hepatitis C virus. When synthetic copies of these miRNAs are introduced the antiviral effect on hepatitis C is replicated, but when these same molecules are neutralized IFN-beta has less antiviral force.

CONTACT

Michael David (University of California San Diego, La Jolla, CA, USA)

Tel: +1 858 822 1108; E-mail: [email protected]

[9] Nanotechnology: A sunny outlook for nanowires (pp 885-889)

In the pursuit of smaller and more efficient solar cell technology, scientists have made a photovoltaic element two-hundred-times thinner than a hair. The nanowire device reported in this week’s Nature could initiate a new generation of solar cells.

The device is a wire made of silicon with three different types of conductivity arranged as shells, like an electric coaxial cable. Incoming light generates electrons in the outer n-type shell, whereas their positive holes are swept into the central p-type layer. Charles M. Lieber and colleagues demonstrate how current drawn from the photovoltaic nanowire can be used to power tiny nanoelectronic circuits.

CONTACT

Charles M. Lieber (Harvard University, Cambridge, MA, USA)

Tel: +1 617 496 3169; E-mail: [email protected]

[10] And finally: Sex determination linked to fitness (pp 909-912)

The genetic mechanisms that determine sex are spectacularly diverse in animals, involving different sets of genes residing on different chromosomes, sometimes even in closely related species. These mysterious patterns can be explained by linking sex determination genes to genes that improve survival rates in one sex to the detriment of the other sex, according to a paper published in this week’s Nature.

The link arises as a selection effect, because a gene that creates a male will benefit from a nearby mutation that improves a male’s chances of survival. G. S. van Doorn and M. Kirkpatrick developed a mathematical model to show how genes that improve fitness in one sex at the expense of the other can hijack sex determination from one chromosome to another, thereby helping to explain the diversity of sex-determination mechanisms seen in nature.

CONTACT

G. S. van Doorn (Santa Fe Institute, Santa Fe, NM, USA)
Tel: +1 505 946 2786; E-mail: [email protected]

ALSO IN THIS ISSUE…

[11] The equilibria that allow bacterial persistence in human hosts (pp 843-849; N&V)

[12] Helicobacter exploits integrin for type IV secretion and kinase activation (pp 862-866)

[13] Nature of the superconductor–insulator transition in disordered superconductors (pp 876-880)

[14] Carbon dioxide release from the North Pacific abyss during the last deglaciation (pp 890-893)

ADVANCE ONLINE PUBLICATION

***This paper will be published electronically on Nature's website on 17 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 18 October, but at a later date.***

[15] An essential role for a CD36-related receptor in pheromone detection in Drosophila

DOI: 10.1038/nature06328

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
Sydney: 2

Wollongong: 2

CANADA:

Montreal: 3, 4

Ottawa: 4

Toronto: 3, 4

Vancouver: 14

Victoria: 14

CHINA
Beijing: 3, 4
Hong Kong: 3, 4
Shanghai: 3, 4

GERMANY

Berlin: 1, 12

Bielefeld: 12

Braunschweig: 12

Garching: 5

Langen: 12

Magdeburg: 12

Tubingen: 12

GREECE
Athens: 2

INDIA
Hyderabad: 1

ISRAEL
Beer Sheva: 13

Jerusalem: 2

Tel Aviv: 5

JAPAN

Hokkaido: 3, 4

Kyoto: 3, 4

Matsumoto: 3, 4

Nagasaki: 3, 4

Tokyo: 3, 4

Tsukuba: 3, 4

Yokohama: 3, 4

NIGERIA

Ibadan: 3, 4

SOUTH AFRICA

Cape Town: 2

SWITZERLAND

Lausanne: 15

Zurich: 14

THAILAND

Bangkok: 3, 4

UNITED KINGDOM

Cambridge: 3, 4

Leicester: 3, 4

Little Chesterford: 3, 4

London: 2, 3, 4

Oxford: 3, 4

UNITED STATES OF AMERICA

Arizona

Tempe: 2

Tuscon: 5

California

Irvine: 14

La Jolla: 3, 4

Menlo Park: 3, 4

Mountain View: 3, 4

Palo Alto: 6

San Diego: 3, 4, 5

San Francisco: 3, 4

Santa Clara: 3, 4

Santa Cruz: 3, 4, 14

Stanford: 6

Sunnyvale: 3, 4

Connecticut

New Haven: 5

District of Columbia

Washington: 4

Florida

Gainesville: 2

Illinois

Chicago: 3, 4

Maryland

Baltimore: 3, 4, 15

Bethesda: 3, 4

Rockville: 3, 4

Massachusetts

Boston: 2, 3, 4

Cambridge: 3, 4, 5, 9

Michigan

Ann Arbor: 3, 11

Missouri

St Louis: 3, 4

New Jersey

East Hanover: 3, 4

Princeton: 14

New Mexico

Santa Fe: 10

New York

Cold Spring Harbor: 3, 4

New York: 3, 11, 15

North Carolina

Chapel Hill: 7

Research Triangle Park: 7

Ohio

Cleveland: 3, 4

Columbus: 3

Oklahoma

Norman: 3, 4

Tennessee

Nashville: 3, 4

Texas

Austin: 10

Houston: 3, 4

Utah

Salt Lake City: 3, 4

Washington

Seattle: 2, 3, 4

PRESS CONTACTS…

For North America and Canada

Katie McGoldrick, Nature Washington

Tel: +1 202 737 2355; E-mail: [email protected]

For Japan, Korea, China, Singapore and Taiwan

Mika Nakano, Nature Tokyo

Tel: +81 3 3267 8751; E-mail: [email protected]

For the UK/Europe/other countries not listed above

Katherine Anderson, Nature London

Tel: +44 20 7843 4502; E-mail [email protected]

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Published: 17 Oct 2007

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