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This press release is copyright Nature.
VOL.437 NO.7063 DATED 27 OCTOBER 2005
This press release contains:
* Summaries of newsworthy papers:
* Genetics: Mapping the human genome for differences to find the genetic causes for disease
* Quantum electronics: Chopping light on chips
* Sleep: Insight and news feature
* Earth science: Telling the time of Earth's core formation
* Behaviour: Chimps don't give a monkey's about their friends
* Physiology: Shark has mammal-like swimming muscles
* Astronomy: Prometheus bound to Saturn's rings
* Neurobiology: Promoting brain cell growth in adult rats
* News: Rocket-fuelled bacteria clean up waste
* Nanotechnology: Molecular motor spins on a surface
* And finally... Einstein's and Darwin's letter-writing habits
* Geographical listing of authors
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[1] & [2] Genetics: Mapping the human genome for differences to find the
genetic causes for disease (pp1299-1320 & 1365-1369; N&V)
Researchers have mapped the most common genetic differences across the
entire genome for 269 different humans in unprecedented detail. A study in
this week's Nature presents a map of these differences, and a second study
uses this data set to identify places in the genome where certain genes are
regulated.
The goal is to understand the complex genetic changes that underlie common
diseases such as cardiovascular disease, cancer, or psychiatric illnesses,
which are still largely unknown. Researchers believe that a big part of the
answer lies in tiny changes in the DNA sequence, called single nucleotide
polymorphisms (SNPs). These are single-letter differences in the DNA between
individuals.
An international team of researchers led by David Altshuler and Peter
Donnelly present a map of more than one million of the most common SNPs
grouped into haplotypes - combinations of SNPs that have travelled together
over evolutionary time. The team checked SNPs from 269 people from four
different populations: 90 people from Nigeria, 90 from the United States, 45
from China and 44 from Japan.
This information will make it unnecessary to sequence the entire genome to
find SNPs that are associated with certain diseases. This is because SNPs
are inherited in groups or haplotypes. To identify a SNP associated with a
certain disease, all researchers have to do is to associate that disease
with a certain haplotype. They can then analyse that haplotype further to
identify the exact SNP that is the cause for the disease.
In the second paper, Vivian Cheung and colleagues have used this large data
set to find associations between certain SNPs and the levels at which
certain genes are expressed. They identify the exact DNA sequence that
controls the expression levels of one gene. It should be possible to use
this approach to understand the genetic causes of traits such as blood
pressure and obesity, they say. A related News & Views article by David B.
Goldstein and Gianpiero L. Cavalleri accompanies this work.
CONTACT:
David Altshuler (The Broad Institute of Harvard and Massachusetts Institute
of Technology, Cambridge, MA, USA. Also at: Massachusetts General Hospital
and Harvard Medical School, Boston, MA, USA)
Tel: +1 617 726 5940; E-mail: [email protected]
Vivian G. Cheung (University of Pennsylvania and The Children's Hospital of
Philadelphia, Philadelphia, PA, USA)
Tel: +1 215 590 4950; E-mail: [email protected]
David B. Goldstein (Duke University, Durham, NC, USA)
Tel: +1 919 684 0896; E-mail: [email protected]
PLEASE NOTE: additional resources for this work will be available from the
relevant section of the Nature press site
[3] Quantum electronics: Chopping light on chips (pp1334-1336; N&V)
Information technologists are increasingly seeking to send and process data
using light as well as electricity, that is, to replace electronics with
optoelectronics. The problem is that silicon, the key fabric for making
microelectronic chips, doesn't handle light very well. A paper in this
week's Nature, shows that another common semiconducting material, germanium,
can be fashioned into optoelectronic devices on silicon chips. Kuo and
colleagues' germanium-based 'light switches' may help to usher in
miniaturized, high-speed and low-power optoelectronic circuits that can be
readily integrated with standard silicon-based chip technologies.
At present, many optoelectronic devices are made from so-called III-V
semiconductors - alloys of exotic elements such as gallium arsenide and
indium phosphide. These materials don't stick comfortably to silicon, and so
they must often be placed on separate chips, complicating the manufacturing
process and compromising compactness and robustness. Germanium is easier to
'grow' on silicon, but it hasn't previously proved very effective for
light-based information processing.
The authors report an 'optical modulator' - a device that effectively turns
a light signal on and off - so that information can be encoded and
transferred just as it is in pulsed electronic signals. The device contains
a multilayered sandwich of very thin layers of pure germanium and a
germanium/silicon mixture, called a quantum-well device because it uses
quantum mechanics to control the light beam that falls on it. A related News
& Views article by Gareth Parry accompanies this research.
CONTACT:
Yu-Hsuan Kuo (Stanford University, Stanford, CA, USA)
Tel: +1 650 725 6909; E-mail: [email protected]
James S. Harris, co-author (Stanford University, CA, USA)
Tel: +1 650 723 9775;E-Mail: [email protected]
Gareth Parry (Imperial College, London, UK)
E-mail: [email protected] (No telephone number currently available, but
please check the press site for updates)
Sleep: Insight and news feature (pp1220-1222 & 1254-1289)
Everyone needs sleep - we spend around a third of our lives in slumber. Yet
there are still many big questions that need to be answered before we can
truly say that we understand it. It is certainly more than merely a rest
phase for the body and brain, as was made clear by the discovery, about 50
years ago, of intense brain activity during the rapid eye movement (REM)
stage of sleep.
This week, Nature presents an Insight on sleep, giving an overview on the
subject and showcasing the answers that we have so far for the three
fundamental questions: what is sleep; what are its mechanisms; and what are
its functions?
Sleep research is shedding light on age-old questions such as what it means
to 'sleep on a problem', and why and when do we dream of waking-life events.
We also now understand many of the brain circuits that control sleep cycles
and this in turn has led to significant progress in treating debilitating
sleep disorders.
This is explored further in a news feature by Alison Abbott, as she examines
the knowledge we have so far of a distressing sleep disorder called REM
sleep behaviour disorder (RBD). Although RBD was first described barely 20
years ago, it is not that uncommon, and curiously a large proportion of
those who have it go on to develop related degenerative diseases, such as
Parkinson's.
The full contents of this Insight and contact details are listed below:
Sleep is of the brain, by the brain and for the brain (pp1254-1256)
CONTACT: J. A. Hobson (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 998 1031; E-mail: [email protected]
Hypothalamic regulation of sleep and circadian rhythms (pp1257-1263)
CONTACT: C. D. Saper (Beth Israel Deaconess Medical Center, Boston, MA, USA)
Tel: +1 617 667 2622; E-mail: [email protected]
Clues to the functions of mammalian sleep (pp1264-1271)
CONTACT: J. M. Siegel (UCLA School of Medicine, North Hills, CA, USA)
Tel: +1 818 891 8612; E-mail: [email protected]
Sleep-dependent memory consolidation (pp1272-1278)
CONTACT: R. Stickgold (Beth Israel Deaconess Medical Center, Boston, MA,
USA)
Tel: +1 617 667 8485, E-mail: [email protected]
Insights from studying human sleep disorders (pp1279-1285)
CONTACT: M. W. Mahowald (University of Minnesota, Minneapolis, MN, USA)
Tel: +1 612 873 6201; E-mail: [email protected]
What are the memory sources of dreaming? (pp1286-1289)
CONTACT: T. A. Neilsen (Université de Montreal and Hopital du Sacré-Coeur de
Montreal, Canada)
Tel: +1 514 338 2222 ext.3350, E-mail: [email protected] /
[email protected]
[4] Earth science: Telling the time of Earth's core formation (pp1345-1348)
The separation of metal into the Earth's core sequestered radioactive
isotopes that can be used as clocks, allowing geologists to estimate the
time at which the Earth's core separated from its rocky outer shell. Two of
these isotope clocks seemed to give conflicting formation times, but a paper
appearing in this week's Nature shows how the problem can be resolved by
considering the effect of the giant impact of a Mars-sized object with the
Earth.
A giant impact is thought to have contributed the last ten percent of the
Earth's mass and formed the Moon. Bernard Wood and Alex Halliday propose
that this would have also changed the conditions of core formation. They put
forward a model that eliminates the discrepancy between the hafnium-tungsten
and uranium-lead isotope clocks if the effects of the oxidation state of the
mantle are taken into account. Wood and Halliday suggest that the
explanation may be that the hafnium-tungsten clock represents the initial
phase of core formation, whereas the upheaval introduced by the giant impact
produced an oxidation state under which a sulphur-rich metal formed, into
which lead would have dissolved readily, in effect resetting the
uranium-lead clock to a younger age.
CONTACT:
Bernard J. Wood (Macquarie University, North Ryde, Australia)
Tel: +61 2 9850 4407; E-mail: [email protected]
[5] Behaviour: Chimps don't give a monkey's about their friends
(pp1357-1359)
Helping others, it seems, is a uniquely human habit. A chimpanzee
behavioural study in this week's Nature shows that they are not interested
in doing their neighbour a good deed, even if it would cause them no
inconvenience at all.
Joan Silk and colleagues presented captive chimpanzees with an apparatus
that gave them a choice between two options. The chimpanzee could choose to
serve only itself with food, or it could select an alternative option that
gave it the same food reward, but also resulted in food being delivered to
another chimpanzee. As the researchers report, the chimpanzees were no more
likely to choose the second option, even though they could see that it would
help out a friend at no cost to themselves.
The results suggest that chimpanzees' actions are not motivated by
'other-regarding preferences', the researchers conclude. In contrast, many
human habits - such as donating blood, giving to charity and punishing
social offenders - show consideration for others. The chimpanzees' lack of
such consideration was made more surprising by the fact that the chimpanzees
used in the study had been living together in stable social groups for many
years.
CONTACT:
Joan B. Silk (University of California, Los Angeles, CA, USA. Currently on
sabbatical in Cambridge, UK)
Tel: +44 0792 975 9697; E-mail: [email protected]
[6] Physiology: Shark has mammal-like swimming muscles (pp1349-1352)
Salmon sharks, which spend their lives in the chilly waters of the North
Pacific, have swimming muscles that only work at relatively high
temperatures, much like those of warm-blooded animals such as mammals,
according to research in this week's Nature. Unlike most other fish, which
conform to their surrounding temperature, the sharks rely on heat generation
within their muscles to maintain their constant swimming.
Researchers led by Robert Shadwick caught three salmon sharks (Lamna
ditropis) in the Gulf of Alaska and measured the temperature at various
sites inside their bodies. The 'red muscles', which power the sharks'
constant swimming and are found at the body's core, had a temperature of up
to 26 degrees Celsius, some 20 degrees warmer than the sea water. Even at 10
degrees above sea temperature, the muscles' performance was impaired by up
to 50%, the researchers found.
The discovery shows how specialized the sharks are for their active
predatory lifestyle, say Shadwick and colleagues. The red swimming muscles
rely on heat produced during muscular contraction to work efficiently - if
their temperature were allowed to drop to that of the surrounding water, the
shark would not be able to carry on swimming. In contrast, the 'white
muscles', which add power for swift bursts of speed, work well across a
range of temperatures, the researchers add.
CONTACT:
Robert E. Shadwick (University of British Columbia, Vancouver, Canada)
Tel: +1 604 827 3149; E-mail: [email protected]
[7] Astronomy: Prometheus bound to Saturn's rings (pp1326-1329)
The gravity of Saturn's small moon Prometheus creates channels and a
'streamer' in the giant planet's F ring, according to research published in
this week's Nature. Prometheus was discovered in 1980 by the Voyager 1
spacecraft, but its effects on Saturn's F ring were only spied after the
Cassini probe arrived at the planet in July 2004.
Carl D. Murray and colleagues show that as Prometheus approaches and recedes
from the F ring every 14.7 hours during its orbit, it draws out strands of
particles from the narrow, twisted ring. This leaves channels running
through the ring, and has also created a 'streamer' of dust linking the ring
to the moon.
The phenomena have not previously been detected in any other planetary ring
system, but computer simulations of the system prove that the disturbance is
caused by a simple gravitational interaction. Prometheus' orbit is at
present gradually moving this little moon towards the F ring, and the
scientists calculate that its perturbations of the F ring will reach a
maximum in December 2009.
CONTACT:
Carl D. Murray (Queen Mary, University of London, London, UK)
Tel: +44 207 882 5456/5440/5555; E-mail: [email protected]
[8] Neurobiology: Promoting brain cell growth in adult rats (1370-1375)
The hippocampus, a region of the brain associated with memory in mammals,
continues producing new nerve cells during adulthood. Stem cells that reside
in the hippocampus give rise to the new neurons, and scientists now have a
better understanding of the molecular signals that control this process.
In a study appearing in Nature, Fred Gage and his colleagues report that the
'Wnt' protein family regulates the birth of new brain cells - both in the
laboratory dish and in live rats. The scientists found that inhibiting Wnt
signalling blocked the formation of neurons in adult rodents and,
conversely, activating it resulted in more neurons. The findings should help
scientists explore the plasticity of the adult brain.
CONTACT:
Fred H. Gage (The Salk Institute, La Jolla, CA, USA)
Tel: +1 858 453 4100 ext.1012; E-mail: [email protected]
News: Rocket-fuelled bacteria clean up waste (pp1227-1228)
Bacteria that make rocket fuel as part of their metabolism are making sewage
and wastewater treatment cheaper and kinder to the environment. The
microbes, whose biology is baffling scientists, have also helped solve a
long-standing mystery about the world's oceans, reports Helen Pilcher in a
news feature in this week's Nature.
The bacteria, provisionally called 'Brocadia anammoxidans', were discovered
in a yeast plant in the Netherlands in the late 1990s. They consume ammonia
and convert it into nitrogen gas, producing hydrazine, or rocket fuel, as
part of this process, known as the anammox reaction. Scientists are still
puzzling over how the bacteria manage to contain this explosive compound,
but have already put them to work breaking down the ammonia-rich waste from
sewage and industrial effluent. These new anammox treatment plants consume
less fuel and cause less pollution than conventional ones and could soon be
commonplace around the world.
Scientists have also recently discovered that the activity of anammox
bacteria explains a 40-year-old mystery: namely, where much of the world's
ammonia disappears to. It seems these bacteria use it to produce up to half
of all the nitrogen in the world's oceans - prompting a major rethink of how
this process works.
[9] Nanotechnology: Molecular motor spins on a surface (pp1337-1340))
The first molecular motor that rotates in just one direction while attached
to a solid surface is unveiled in this week's Nature.
Although similar motor molecules have been made before, they have only
worked in liquid solutions. Useful nanomachines built from individual
molecules would need motors that could be anchored to a solid. Ben L.
Feringa and colleagues' motor is based on a molecule with two 'legs' that
has sulphur atoms at its 'feet'. These atoms cling onto the surface of a
tiny gold nanoparticle.
When the molecule is exposed to light and heat, it swivels round at the
waist. The rotary motion is restricted to one direction by chemical groups
in the upper portion of the motor that act as a ratchet, preventing the
molecule from slipping back in the wrong direction.
CONTACT:
Ben L. Feringa (University of Groningen, Groningen, The Netherlands)
Tel: +31 50 363 4278; E-mail: [email protected]
[10] And finally... Einstein's and Darwin's letter-writing habits (p1251)
Einstein and Darwin were prolific correspondents, sending and receiving
hundreds of letters each year. They replied to many of the letters they
received, usually within ten days but sometimes with a delay of up to two
years. Despite these fluctuations, their correspondences showed long-range
order, following the same patterns as modern email communications, according
to a Brief Communication in this week's Nature.
In his lifetime, Darwin sent 7,591 letters and received 6,530; Einstein sent
more than 14,500 letters and received 16,200, with a decrease in
correspondence during the Second World War. J. G. Oliveira and A.-L.
Barabasi analysed the time it took for the scientists to reply to letters.
They found that the distribution of waiting times for a response from either
scientist followed approximately the same power law as email today, despite
their sometimes lengthy delay in replying. Einstein and Darwin have exposed
a fundamental pattern of human communication dynamics that is shared by the
average person in their mundane prioritization of inbox items each morning.
CONTACT:
Albert-László Barabási (University of Notre Dame, Notre Dame, IN, USA. Also
at: Dana-Farber Cancer Institute, Harvard University, Boston, MA, USA)
Tel: +1 617 582 8366; E-mail: [email protected]
ALSO IN THIS ISSUE...
[11] Evolution of indirect reciprocity (pp1291-1298)
[12] Repetitive shuttling of a motor protein on DNA (pp1321-1325; N&V)
[13] Observation of spin Coulomb drag in a twodimensional electron gas
(pp1330-1333)
[14] Low-latitude seasonality of Cretaceous temperatures in warm and cold
episodes (pp1341-1344)
[15] Reinforcement drives rapid allopatric speciation (pp1353-1356)
[16] Regulation of Lethal giant larvae by Dishevelled (pp1376-1380)
[17] A heterodimeric complex that promotes the assembly of mammalian 20S
proteasomes (pp1381-1385)
[18] The histone H3.3 chaperone HIRA is essential for chromatin assembly
in the male pronucleus (pp1386-1390)
[19] Chaperone mutation in Tn syndrome (p1252)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 26
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 27 October, but at a later date.***
[20] The AID antibody diversification enzyme is regulated by protein
kinase A phosphorylation
DOI: 10.1038/nature04255
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
Atherton: 15
St Lucia: 15
AUSTRIA
Vienna: 11
CANADA
Alberta: 6
Montreal: 1
Ottawa: 1
CHINA
Beijing: 1
Hong Kong: 1
Shanghai: 1
DENMARK
Copenhagen: 17
FRANCE
Marseille: 14
Villeurbanne: 18
GERMANY
Bochum: 14
Munich: 8
JAPAN
Hokkaido: 1
Kanagawa: 1
Kawagachi: 17
Kyoto: 1
Matsumoto: 1
Nagasaki: 1
Tokyo: 1, 17
Tsukuba Science City: 1
NIGERIA
Ibadan: 1
PORTUGAL
Aveiro: 10
THAILAND
Bangkok: 1
THE NETHERLANDS
Amsterdam: 14
Groningen: 9
UNITED KINGDOM
Bath: 18
Bristol: 4
Cambridge: 1
London: 1, 7
Oxford: 1, 4
Walden: 1
UNITED STATES OF AMERICA
California
Berkeley: 13, 15
La Jolla: 6, 8
Los Angeles: 5
Mountain View: 1
Oceanside: 6
Palo Alto: 1, 3
Pasadena: 13
Poway: 1
San Diego: 1
San Francisco: 1
Santa Barbara: 13
Santa Cruz: 1
Stanford: 3
Colorado
Boulder: 7
District of Columbia
Washington: 1
Georgia
Atlanta: 5
Illinois
Urbana: 12
Indiana
Notre Dame: 10
Louisiana
New Iberia: 5
Maryland
Baltimore: 1, 8
Bethesda: 1
Rockville: 1
Massachusetts
Boston: 1, 10
Cambridge: 1, 11
North Dartmouth: 6
Michigan
Ann Arbor: 1
Missouri
St Louis: 1, 12
New Jersey
East Hanover: 1
New York
Cold Spring Harbor: 1
Ithaca: 7
New York: 16
North Carolina
Raleigh: 1
Ohio
Cleveland: 1
Oklahoma
Norman: 1
Oklahoma City: 19
Pennsylvania
Philadelphia: 2
Tennessee
Nashville: 1
Texas
Bastrop: 5
Houston: 1
Utah
Salt Lake City: 1
Washington
Seattle: 1
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
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Katharine Mansell, Nature London
Tel: +44 20 7843 4658; E-mail: [email protected]
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