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This press release is copyright Nature.
VOL.452 NO.7186 DATED 27 MARCH 2008
This press release contains:
· Summaries of newsworthy papers:
Human evolution: First hominin of Western Europe
Therapeutics: Genetic blindness treatments emphasize immune role
Biology: MicroRNA silencing in non-human primates
Genomics: Complexity and evolution
Carbon nanotubes: Spinning into control
Palaeoclimatology: Stepwise oxygenation of the ancient ocean
And finally… Retinal cells that respond to upward motion
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Human evolution: First hominin of Western Europe (pp 465-469)
Scientists in Spain have discovered teeth and a jaw bone believed to be from the oldest-known hominin in Western Europe. The fossils — over one million years old — were found with lithic tools and faunal remains, and are thought to be the most accurately dated evidence of human occupation in the continent.
Dating sites where hominin fossils are found remains controversial. In Nature this week, Eudald Carbonell and colleagues report the discovery of a human lower jaw associated with stone tools and animal bones from a complex of human-fossil-bearing sites in Atapuerca, northern Spain. The team were able to date the fossils using a variety of techniques, such as palaeomagnetism and the radioactive decay of isotopes in the sediments. They also used biostratigraphy to calculate the age of the rocks in which the fossils were found — between 1.1 and 1.2 million years old.
The lithic tools associated with the remains show traces of human activity — methods such as flint knapping and hammering are evident, and human activity is also indicated by cut marks made on animal bones. The faunal assemblage also provided valuable information about the age of the fossils, being much more primitive than the remains in nearby sites.
The authors assign the fossils to the species Homo antecessor, a possible ancestor of Neanderthals and modern humans. The fossil evidence, together with remains from other sites, suggest that Western Europe was settled during the early Pleistocene epoch by a hominin population coming from the east.
CONTACT
Eudald Carbonell (Institut Català de Paleoecologia Humana i Evolució Social (IPHES,) Tarragona, Spain)
Contact through assistant:
Aida Carbonell
Tel: +34 608 72 90 03; E-mail: [email protected]
Jose Maria Bermúdez de Castro (Centro Nacional de Investigación sobre la Evolución Humana (CENIEH,) Burgos, Spain)
Tel: +34 626 409 530; E-mail: [email protected] Co-author
Media office contacts:
Cinta Bellmunt (IPHES)
Tel: +34 639 569 725; Email: [email protected]
Amor Barros (CENIEH)
Tel: +34 947 255 006; E-mail: [email protected]
[2] Therapeutics: Genetic blindness treatments emphasize immune role (AOP)
DOI: 10.1038/nature06765
***This paper will be published electronically on Nature's website on 26 March at 1800 London time / 1400 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 27 March, but at a later date. ***
A promising treatment for age-related macular degeneration — responsible for up to 50 million cases of blindness worldwide — works by a more general mechanism than had previously been thought, according to a study online in this week’s Nature. The discovery raises the possibility that the success of the treatment, thought to require highly specific RNA molecules, might, in fact, result from a more generalized immune response to RNA.
Late-stage age-related macular degeneration patients suffer blindness when excess blood vessel cells proliferate in the retina, preventing it from functioning properly. Trial treatments have attempted to prevent this by injecting molecules called small interfering RNAs (siRNAs) into the eye, to bind to and specifically switch off a gene that promotes such cell proliferation.
But in studies on mice, researchers led by Jayakrishna Ambati found that the effect also seems to work with other siRNA molecules that have no complementarity to this gene. This, they suggest, means that the treatment works not by inhibiting expression of a particular gene, but by boosting the immune system to ward off the encroaching cells. This insight may change our understanding of how to tackle age-related blindness.
CONTACT
Jayakrishna Ambati (University of Kentucky, Lexington, KY, USA)
Tel: +1 859 323 0686; E-mail: [email protected]
[3] Biology: MicroRNA silencing in non-human primates (AOP)
DOI: 10.1038/nature06783
***This paper will be published electronically on Nature's website on 26 March at 1800 London time / 1400 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 27 March, but at a later date. ***
Researchers have effectively silenced microRNAs (miRNAs) in monkeys for the first time, targeting a liver-specific miRNA and reducing blood cholesterol as a result. The research is the first demonstration of miRNA silencing in primates and supports the potential of new nucleic-acid-based therapeutics, as many disease-associated genes are regulated by miRNAs.
Previous work has demonstrated that short interfering RNAs can be administered in primates to reduce expression from select messenger RNAs. Sakari Kauppinen and colleagues now show that a therapeutic effect can also be achieved by targeting miRNAs; their results are reported online in Nature this week. The authors synthesized a short DNA sequence composed of modified nucleotides that had complementarity to a miRNA that regulates a gene involved in cholesterol metabolism. Injection of this oligonucleotide led to a reduction in serum cholesterol without detectable toxicity in the monkeys.
The research is an important step in understanding the functions of miRNAs and in the future development of oligonucleotide-based therapeutics.
CONTACT
Sakari Kauppinen (Santaris Pharma, Hørsholm, Denmark)
Tel: +45 4517 9800; E-mail: [email protected]
Joacim Elme´n (Santaris Pharma, Hørsholm, Denmark) Co-author
Tel: +45 4517 9853; E-mail: [email protected]
Morten Lindow (University of Copenhagen, Denmark) Co-author
E-mail: [email protected]
[4] Genomics: Complexity and evolution (pp 470-472)
Contrary to popular belief, complex organisms do not evolve more slowly than their simpler counterparts. Research in Nature this week looks at the question of multiple effects from one genetic mutation and concludes there is no ‘cost of complexity’ for higher organisms.
As more genetic sequence data are generated, evolutionary biology questions about inheritance and phenotypes can be examined with sophisticated analyses. Günter Wagner and colleagues address a fundamental problem in evolutionary biology, the relationship between an organism’s complexity and its ability to evolve. They look at the effect of pleiotropy — multiple effects from one genetic mutation — on the skeletal characteristics of mice. The results suggest that there is no ‘cost of complexity’ for higher organisms, because most mutations affect few traits and the size of the effects does not increase with complexity.
CONTACT
Günter Wagner (Yale University, New Haven, CT, USA)
Tal: +1 203 432 9998; E-mail: [email protected]
[5] Carbon nanotubes: Spinning into control (pp 448-452; N&V)
In carbon nanotubes, spin and orbital motion of the electrons are more strongly coupled than previously thought, and this could open up new possibilities for manipulating electron spin in device applications.
Carbon-based materials are seen as promising candidates for applications such as spintronics and as spin qubits (for quantum computing), as their electron spins are thought to be exceptionally stable. In particular, it has been assumed that the effect of an electron’s spin coupling to its orbital motion — a source for spin decoherence — is negligible. In Nature this week, Paul McEuen and colleagues disprove this assumption, using detailed electronic transport measurements on high quality, clean, single walled carbon nanotubes: the team observe direct signatures of electron spin–orbit coupling. Although at one level this finding might seem troubling for the envisaged applications — for which weak spin–orbit coupling is seen as an advantage — it could instead be a boon by opening up new desirable ways to control quantum information.
CONTACT
Paul McEuen (Cornell University, Ithaca, NY, USA)
Tel: +1 607 255 5193; E-mail: [email protected]
Arne Brataas (Norwegian University of Science and Technology, Trondheim, Norway) N&V author
Tel: + 47 73 59 36 47; E-mail: [email protected]
[6] Palaeoclimatology: Stepwise oxygenation of the ancient ocean (pp 456-459)
It is thought that oxygenation of the Earth’s atmosphere proceeded in two steps, near the start and end of the Proterozoic eon — which lasted from around 2,500 to 542 million years ago — but how the ocean responded to these changes is something of a mystery. A paper in this week’s Nature offers fresh insight into the ocean’s changing oxidation state during this critical period.
Clint Scott and colleagues collected molybdenum and total organic carbon data from black shales, which enabled them to sketch out a profile of the ocean’s oxidation history. Molybdenum is an essential participant in nutrient cycling and its availability is highly sensitive to the Earth’s oxidation state. They found that there was only mild oxidative weathering of the continents before about 2,200 million years ago, but this weathering became more persistent and vigorous some 50 million years later — roughly 200 million years after the initial rise in atmospheric oxygen.
Towards the end of the Proterozoic at around 551 million years ago, the team’s analysis suggests that the deep ocean had also become oxygenated and that today’s biogeochemical cycles were established — setting the stage for the appearance of the first large animals and the evolutionary course of life on Earth.
CONTACT
Clint Scott (Univeristy of California, Riverside, CA, USA)
Tel: +1 951 827 1227; E-mail: [email protected]
[7] And finally… Retinal cells that respond to upward motion (pp 478-482)
Scientists have identified a unique population of cells that help the eye to process upward movement. The cells differ from previously described directionally selective cells in the retina, the part of the eye responsible for detecting light.
Mammals’ retinas contain networks of neurons that process various features in the visual world, including the direction of moving stimuli. Joshua Sanes and colleagues use a transgenic molecular marking method to identify a new class of retinal ganglion cells in mice; they report their finding in Nature this week. The cells are ‘OFF’ — they respond to decreases in light intensity and to visual objects moving upwards. The cells have a distinctively asymmetrical structure that may contribute to their ability to process upwards motion, and have quite different connectivity from other known directionally selective cells. This reveals the potential for using such molecular genetic approaches for discovering new cell types and circuits in the brain.
CONTACT
Joshua Sanes (Harvard University, Cambridge, MA, USA)
Tel: +1 617 496 8683; E-mail: [email protected]
ALSO IN THIS ISSUE…
[8] Compartmentalized dendritic plasticity and input feature storage in neurons (pp 436-441; N&V)
[9] Lower-crustal intrusion on the North Atlantic continental margin (pp 460-464)
ADVANCE ONLINE PUBLICATION
***Thse papers will be published electronically on Nature's website on 26 March at 1800 London time / 1400 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 27 March, but at a later date. ***
[10] Retinotopic order in the absence of axon competition
DOI: 10.1038/nature06816
[11] TGF-b-induced Foxp3 inhibits TH17 cell differentiation by antagonizing RORct function
DOI: 10.1038/nature06878
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:
Montreal: 6
Winnipeg: 6
CHINA
Beijing: 6
DENMARK
Copenhagen: 3
JAPAN
Nagoya: 2
Osaka:
SPAIN
Burgos: 1
Madrid: 1
Tarragona: 1
Zaragoza: 1
UNITED KINGDOM
Aberdeen: 9
Brighton: 4
Cambridge: 9
Lincolnshire: 9
Liverpool: 9
Newcastle: 6
UNITED STATES OF AMERICA
Arizona
Tempe: 6
California
El Portal: 1
Riverside: 6
San Francisco: 10
Stanford: 3
Connecticut
Hamden: 3
New Haven: 3
District of Columbia
Washington: 6
Illinois
Chicago: 2
Indiana
West Lafayette: 1
Kentucky
Lexington: 2
Massachusetts
Cambridge: 7
Natick: 3
Michigan
Ann Arbor: 1
Missouri
St Louis: 4
New York
Ithaca: 5
New York: 11
North Carolina
Chapel Hill: 2
Greensboro: 2
Oregon
Portland: 2
Pennsylvania
Philadelphia: 2
Utah
Salt Lake City: 2
Virginia
Ashburn: 8
Washington
Seattle: 11
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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