news20091211gdn1

[News] from [guardian.co.uk]

[Environment > Copenhagen Climate change conference 2009]
Copenhagen: Barack Obama backs Norway-Brazil forest protection plan
US president endorses scheme proposed by Norway and Brazil that would protect the world's rainforests with funding from rich countries which cannot cut their emissions at home
John Vidal in Copenhagen
guardian.co.uk, Thursday 10 December 2009 17.12 GMT Article history

The US president, Barack Obama, made his first public intervention in the Copenhagen climate summit today by backing a plan put forward by Norway and Brazil which would protect the world's rainforests with funding from rich countries that cannot meet their commitments to cut emissions domestically.

Speaking after he accepted the Nobel peace prize in Oslo, Norway, Obama said: "I am very impressed with the model that has been built between Norway and Brazil that allows for effective monitoring and ensures that we are making progress in avoiding deforestation of the Amazon.

"It's probably the most cost-effective way for us to address the issue of climate change - having an effective set of mechanisms in place to avoid further deforestation and hopefully to plant new trees."

The president is not due at the conference for another week but his intervention comes at a critical time in the summit where negotiations on deforestation are moving rapidly.

The scheme is seen as attractive because pilot studies have shown it to be effective and has the backing of Prince Charles's Rainforest Project.

Countries are more or less unanimously behind finding a way to reduce deforestation, which accounts for 16% of world greenhouse gas emissions, but are encountering sticking points which require the intervention of heads of state.

At least 20 different plans for Reduced deforestation and degradation (Redd) plans have been put forward by many different countries, but talks are in the balance over the rights and safeguards for people who live in or depend on the forests; how the money can be prevented from falling prey to corruption; how to measure and verify claims of protection and the future of existing forest industries.

Rich countries are eager to find a solution because a successful deal will provide them with a solution to "offset" hundreds of millions of tonnes of carbon. Poor countries, especially in the tropics, are equally keen because they stand to receive vast cash flow for protecting their forests.

Brazil is critical in forest talks because it not only is responsible for nearly 20% of all global forest emissions, but it has the largest swath of trees in the world and therefore stands to make more money than anyone else by protecting them.

Today, the talks were moving quickly. The EU has proposed a 50% cut in the rate of deforestation by 2020 and a complete halt by 2030. But Brazil said it did not want a specific target or timetable, arguing that Redd would be voluntary, and that developing countries needed to see how much money they might receive before committing themselves to such an ambitious global scheme.

Obama's endorsement of the Brazil-Norway plan was welcomed by non-governmental organisations who said that it indicated that money had a good chance of being found to set up Redd schemes.

A global deforestation initiative would take many years to establish, and would cost hundreds of millions of dollars to set up because it would require satellite technology and pilot projects. In addition, governments will have to pass domestic legislation before it begins.

Also in Copenhagen, Google demonstrated a new technology prototype that enables online, global-scale observation and measurement of changes in the Earth's forests. The technology, which combines satellite photography, area-measuring software and a "cloud" processing engine, will be offered as not-for-profit service to all nations.


[Environment > Copenhagen Climate change conference 2009]
Vulnerable nations at Copenhagen summit reject 2C target
Alliance of Small Island States say any deal that allows temperatures to rise by more than 1.5C is 'not negotiable'
John Vidal in Copenhagen
guardian.co.uk, Thursday 10 December 2009 13.55 GMT Article history

More than half the world's countries say they are determined not to sign up to any deal that allows temperatures to rise by more than 1.5C - as opposed to 2C, which the major economies would prefer.

But any agreement to reach that target would require massive and rapid cuts in greenhouse gas emissions combined with removal of CO2 in the atmosphere. An extra 0.5C drop in temperatures would require vastly deeper cuts in carbon dioxide and up to $10.5 trillion (£6.5tr) extra in energy-related investment by 2030, according to the International Energy Agency.

Holding temperatures to an increase of 1.5C compared to preindustrial levels would mean stabilising carbon concentrations in the atmosphere at roughly 350 parts per million (ppm), down from a present 387ppm. No technology currently exists to feasibly remove CO2 from the atmosphere on a large scale.

The temperature issue was starkly highlighted yesterday when Tuvalu, one of the world's most climate-threatened countries, formally proposed that countries sign up to a new, strengthened and legally binding agreement that would set more ambitious targets than what is presently being proposed. This divided G77 countries, some of whom led by China and India argued against it, fearing that it would replace the Kyoto protocol.

But they were supported by many of the vulnerable countries, from sub-Saharan Africa as well as the small island states, with passionate and powerful statements about the catastrophic impact of climate change on their people.

"Tuvalu has taken a strong stand to put the focus back on their bottom line. Nothing but a legally binding deal will deliver the strong commitments to urgent action that are needed to avoid catastrophe, especially to the most vulnerable countries and people," said the Oxfam spokesman Barry Coates.

Today the Alliance of Small Island States (Aosis), a grouping of 43 of the smallest and most vulnerable countries, including Tuvalu, said any rise of more than 1.5C was not negotiable at Copenhagen. They are backed by 48 of the least developed nations.

But the UN conference chief, Yvo de Boer, implied this morning that the proposal had little chance of being adopted. "It is theoretically possible that the conference will agree to hold temperatures to 1.5C but most industrialised countries have pinned their hopes on 2C," he said.

The 2C figure, which was included in the leaked draft negotiating text prepared by the summits host Denmark has emerged as the figure favoured by large economies and the likeliest to be adopted. But the poorest countries say that latest science implies that a 2C warming would lead to disastrous consequences – for example from sea level rise.

"We have two research stations, one in the Pacific and one in the Caribbean. They both suggest a rise of 2C is completely untenable for us," said Dessima Williams, a Grenadian diplomat speaking for Aosis.

"Our islands are disappearing, our coral reefs are bleaching, we are losing our fish supplies. We bring empirical evidence to Copenhagen of what climate change is doing now to our states," she said.

news20091211gdn2

[News] from [guardian.co.uk]

[Environment > Food]
Eat less meat and dairy: official recipe to help health of consumers – and the planet
Shrinking of food and drink industry likely, says report
Felicity Lawrence
The Guardian, Friday 11 December 2009 Article history

The first official recommendations for a diet that is both healthy and good for the environment are published today, and they are likely to be seen as an assault on the UK's current food system.

To fight climate change and tackle the growing crisis of diet-related diseases such as diabetes, heart disease and cancer, British consumers must cut down on meat and dairy produce, reduce their intake of processed foods and curb waste.

These are the three priorities identified in a report by the government's independent advisory body on sustainability, the Sustainable Development Commission (SDC), which calls for radical changes in patterns of consumption.

The report – which will dismay many in the livestock and processed food industries – will feed into all government departments and procurement agencies. Well-placed sources say it has created tension between Whitehall departments and advisers over its potential impact.

The study acknowledges that cutting processed food and reducing consumption of intensively-produced meat and dairy foods could lead to a shrinking of the UK food and drink industry.

The UK's retail supply system would also be affected – the SDC report recommends that people reduce energy consumption by shopping more on foot or over the internet and that they replace bottled water with tap water.

While about 18% of the UK's greenhouse gas emissions are related to food and drink consumption and production, the industry is the single biggest manufacturing sector in the UK, accounting for 7% of GDP and employing 3.7m people. The recommended shift away from meat and dairy to more seasonal and field-grown (as opposed to glasshouse-grown) vegetables and fruit would also hit the UK's already hardpressed livestock farmers.

The way that farmland is used would have to change. Grass-fed rather than grain-fed animals are a more sustainable use of resources, the report says. There should be "an increase in consumption of foods produced with respect for wildlife and the environment, eg organic," it adds. The SDC also highlights soya and palm oil as "hotspots" of the sort of consumption that damages the environment while providing calories of low nutritional value. It estimates that 70,000 premature deaths in the UK could be avoided if diets matched healthy guidelines.

Figures released yesterday by the NHS information survey showing that almost one in four boys and more than one in five girls in England are overweight or obese at the start of their school lives added urgency to the debate. SDC commissioner Professor Tim Lang said the recommendations represented the first coherent advice on a sustainable diet. "So far we've had fragmented and contradictory thinking on what dietary intakes should be. Advice to consumers ought to change and stop compartmentalising issues.

"Cutting down on meat and dairy, eating only sustainably sourced fish, fruit and vegetables, would all help reduce the impact of our food system as well as improving health," he said.

The government's approach to addressing the priorities in the report has been "mixed", according to the SDC. Food waste and consumers' shopping have received high-profile attention but cutting meat and dairy and junk food has not, it argues.

Recommended diet for a warming planet
1 Cut consumption of meat and dairy products

Health benefits: Reduces incidence of cardiovascular disease, of some forms of cancer, and of animal-borne infections. Environmental benefits: Large reduction in greenhouse gas (GHG) emissions, slowing of deforestation, freeing of farm land for other use, freeing of water resources, slowing loss of biodiversity, lower food prices and cheaper diets, higher employment. Negative impacts: Decline in UK and global livestock industry, potential increase in deficiencies of iron, calcium and zinc.

2 Cut consumption of processed foods and drinks, especially fatty, sugary ones and stimulant drinks

Health benefits: Reduced obesity, reduced tooth decay, likely to particularly improve health of low income groups. Environmental benefits: Cut in GHG emissions from energy-intense production of highly processed foods and bottled water. Reduced land use. Negative impacts: Cut in size of UK food manufacturing industry.

3 Reduce waste

Consume no more calories than needed, accept different standards of food quality and that some foods may not always be available in UK. Health benefits: Cut in obesity problems, cheaper diet would benefit poor particularly; less air pollution from food freight, less food poisoning. Environmental benefits: Reduced GHG emissions, reduced waste in agriculture, reduced imported food and associated emissions. Negative impacts: Cut in size of food and drink and supply industry, could increase consumption of processed fruit and vegetables of lower nutritonal quality, reduction in trade with developing countries.

Other recommended changes:

> Eat more fruit and vegetables

> Eat only fish from sustainable stocks

> Eat more foods produced with respect for wildlife and environment• Shop on foot or on internet and cook and store food in energy-saving ways

> Drink tap water, not bottled water

Source: SDC advice to government on priority elements of sustainable diets, December 2009


[Environment > Energy efficiency]
Chancellor announces boiler scrappage scheme in pre-budget report
Some 125,000 new boilers and doubling of commitment to carbon capture and storage included in Alistair Darling's speech
Alok Jha, green technology correspondent
guardian.co.uk, Wednesday 9 December 2009 15.58 GMT Article history

Householders will be able to trade in their old boilers for newer, more efficient models under plans announced today by the chancellor, Alistair Darling.

The cash is part of a package of environmentally friendly measures (pdf) unveiled in the government's pre-budget report.

Announcing funding for carbon capture projects and tax breaks for those generating their own electricity, the chancellor said that Britain had to conserve more energy to cut carbon emissions.

An extra £200m will go into helping people make their homes more energy-efficient through measures such as insulation, supporting around 75,000 households. "This will go alongside further requirements from the energy companies, up to £300m overall, to provide discounts on energy bills to another 1m low-income households," Darling said.

Paul King, the chief executive of the UK Green Building Council, welcomed the energy-efficiency moves. "They help raise the profile of home energy efficiency and provide some support to the emerging low carbon refurbishment industry. However, we're still just tinkering around the edges of what is possible. Householders need help refurbishing their whole home, not just their boiler."

There are around 4m G-rated gas boilers in the UK, according to Philip Sellwood, the chief executive of the Energy Saving Trust. "If these were all replaced with A-rated boilers it would save almost 4.5m tonnes of CO2 per year, the equivalent of 830,000 household's emissions, so the scheme announced today has real promise," he said. Upgrading to an A-rated condensing boiler could save a household £310 a year in bills.

Homeowners with wind turbines or solar panels will also benefit from feed-in tariffs starting next April, which will guarantee a price for any electricity fed into the national grid. The government said it could provide an average of £900 - tax free - per year, for a household generating green power.

Darling said the government will also invest in low-carbon sectors such as wind power and increase its commitment to carbon capture and storage (CCS) technology. The CCS money will fund four demonstration projects in the UK.

Darling said the environmental sector was an opportunity to produce create new high-skilled, highly paid jobs for the UK. "Today I can redirect existing funding, and invest in wind power, renewable energy and other green industries," he said.

"Through the Innovation Investment Fund and the Carbon Trust's venture capital scheme, we will support at least £160m of public and private investment in low-carbon projects. We will also invest £90m in the European Investment Bank's new 2020 fund, which will enable €6.5bn of finance for green infrastructure projects."

Greenpeace's executive director, John Sauven, said a bold move would have been to scrap the UK's Trident nuclear weapon system, which could have saved £100bn, and use the money to create a green investment bank. "This would help British companies invest in clean technology, and bring thousands of new jobs and much needed energy security to the UK. Instead we've got a few tax breaks and lots of rhetoric, but words alone won't build a low-carbon economy."

news20091211sa

[Environment] from [scientificamerican.com]

[Greenwire > Energy & Sustainability]
December 10, 2009
Broader Interpretation Sought for Endangered Species Act
Scientists Ask Interior Department to Rescind Bush-era Restrictions
By Noelle Straub

Nearly 130 scientists today asked the Interior Department to change a policy set under the Bush administration guiding how agencies decide whether a species is endangered.

At issue is guidance issued in 2007 that redefined when the Fish and Wildlife Service would protect a species as "endangered" or "threatened." The Endangered Species Act requires protection of any species in danger of extinction throughout all or a significant portion of its range.

Then-Interior Solicitor David Bernhardt issued guidance that recommended agencies focus on plants and animals most at risk in their current locations, rather than throughout their historic range or in other locations where species may be healthy.

The scientists want Interior Secretary Ken Salazar to rescind that memorandum. They say it sharply limits the scope of the ESA by limiting analysis to species' current range and by specifying that species will be listed only in the portion of range considered significant.

"We are concerned that these interpretations will result in imperiled species not receiving protection and limit where species that are listed are ultimately recovered," they wrote. "We are also concerned that the memorandum will limit protection for endangered species to small portions of range where they may not be recoverable."

Duke University's Stuart Pimm, Michigan Tech University's John Vucetich and the Center for Biological Diversity's Noah Greenwald headed up the letter. They said the policy is limiting protections for species including the gray wolf and Colorado River cutthroat trout.

"Ignoring loss of range when determining whether species require protection as endangered species makes little sense," Pimm said in a statement. "Resetting the clock to the present day could result in many species that have lost significant portions of range being wrongfully denied protection."

An Interior spokeswoman said the department is reviewing the letter.

The Bush-era memorandum was written to respond to the department's losing record in court on its previous interpretation of species' range. A group of career Interior lawyers contributed to the guidance and all signed onto the document.


[News > Energy & Sustainability]
December 10, 2009
In Deep Water: Will Essential Ocean Currents Be Altered by Climate Change?
Scientists are struggling to get a grasp on the huge volumes of water flowing through the world's oceans
By Nancy Bazilchuk

Every second, a vast quantity of cold, dense seawater equal to six times the combined flow of every land river on Earth streams over an ocean-floor ridge that stretches between Greenland and Scotland. This deep southbound current, flowing from the Norwegian, Iceland and Greenland seas into the North Atlantic, is the lower limb of the Gulf Stream and its northerly extension, a great conveyor belt of ocean heat and salt that transports warm tropical water north from the equator. Most climate change models predict global warming will slow these flows, in part by altering a key component of the Atlantic's circulation, called deep-water formation. If that happens, northern Europe will cool—or warm less severely—as the rest of the globe swelters.

Understanding the role that deep-water formation plays in driving this grand circulation pattern, more formally called the Atlantic Meridional Overturning Circulation (AMOC), will help scientists predict how global warming will affect climate—both in and beyond the Northern Hemisphere. Shifts in the Atlantic's circulation patterns will alter African and Indian monsoon rainfall as well as hurricane patterns in the South Atlantic, resulting in "a profound impact on the global climate system," according to a team of international scientists asked by the U.S. government to evaluate the potential for abrupt climate change.

Oceanographers have been using moored acoustic Doppler current profilers and temperature sensors for the last decade to measure deep water as it pours over the Greenland–Scotland Ridge on its way south. They're both trying to establish the natural yearly and decadal variations in its creation as well as look for evidence of changes from human-generated temperature increases. "Our assumption is that when we are studying the exchange between the North Atlantic and the Nordic Seas, that this deep conduction and cooling of ocean water is important to the AMOC," says Svein Østerhus, an oceanographer at the Bjerknes Center for Climate Research in Bergen, Norway, who has been investigating the flows.

Deep-water formation is just what it sounds like: As the Atlantic's surface waters travel north they become cooler and denser, so that by the time they reach the Arctic they are cold enough to sink to the ocean bottom. The sinking water pulls warm surface waters like the Gulf Stream north, which in turn leaves a void that pulls deep, colder water south. If global warming inhibits the formation of deep water, the flows across the Greenland–Scotland Ridge should slow.

But it's not that simple. Between the 1950s and the 1990s, the deep water in the Nordic Seas was both warmer and increasingly less salty. As a result, "we had quite remarkable changes in deep-water formation," Østerhus says. Nevertheless, the flow of deep water headed south over the Greenland–Scotland divide has remained stubbornly stable for the past 50 years, Østerhus and his colleagues reported a paper in Nature late last year. The reasons for these counterintuitive findings are not clear, he says. It may be that deep water is pooling behind the Greenland–Scotland Ridge, providing a reservoir from which older deep water can flow when production is slowed. Østerhus's colleague, Detlef Quadfasel, an oceanographer at the University of Hamburg, thinks that part of the explanation is that "this is a nonlinear system—it can simply jump from one state to another."

Now Østerhus will travel in January to the other place on the planet where deep water forms—the Antarctic. The Weddell Sea off Antarctica is home to the coldest, densest deep water on Earth. Østerhus's mission will be to retrieve data from a string of high-tech monitors put in place there last February, with the hope of understanding how Antarctic deep-water formation affects the churning of the Atlantic's currents far to the north. There is very little information on deep-water formation in the Antarctic, and Østerhus will collect basic data on temperatures, velocities and salinity that will form the foundation for later comparisons.

"Deep-water formation in the Arctic and Antarctica are of equal importance, and they are linked," he says. "Deep water formed in the Arctic can be traced the whole way south to Antarctica and deep water formed in the Weddell Sea can be traced as far north as Ireland. A change in the Antarctic deep-water formation may have an impact on the circulation of the North Atlantic."

As Østerhus and his colleagues scramble to understand what's going on at the most distant edges of the Atlantic, roughly two dozen other projects are measuring the Atlantic’s flows elsewhere, including a string of instruments from the Bahamas to Morocco. And in late September an international team proposed that the entire network be transformed into a more formal international monitoring effort in the hopes of helping humankind prepare for what global warming will bring.

"We rely on climate forecasting models to understand climate change, but not all models are in agreement," says William Johns, a University of Miami oceanographer who helped write the abrupt climate change report for the U.S. government. "We have to refine these models to get some idea of what we are going to have to get adapted to—and exactly how much warming we will get in the North Atlantic depends on how much this circulation really does slow down."

news20091211nn1

[naturenews] from [nature.com]

[naturenews]
Published online 10 December 2009 | Nature | doi:10.1038/news.2009.1137
News
Dinosaurs diversified before spreading around the world
Fossil finds suggest that South America was the wellspring of the dinosaurs.
Rex Dalton

Fossils found in the US state of New Mexico are providing strong evidence that dinosaurs originated in what is now South America, and had already evolved into three main groups before spreading around the world.

The fossils — of a new species, named Tawa hallae — back more than 200 million years, to when Earth's land masses were joined together as the supercontinent Pangaea. They retain features from the earliest dinosaur specimens, found in South America.

Dinosaurs are thought to have first evolved about 230 million years ago, their populations yo-yoing until a cataclysmic event wiped them out about 65 million years ago.

The find suggests that the early dinosaurs — classified as theropods, sauropods and ornithischians — migrated from South America around the rest of Pangaea roughly 220 million years ago. The animals then settled in the most suitable climates at different latitudes, says palaeontologist Sterling Nesbitt, of the University of Texas at Austin, who led the study.

Nicknamed Tawa, the two-legged creature studied by Nesbitt's team lived about 215 million years ago, and shares key features with the earliest known theropods, including air sacs in bones, hips with open sockets, and teeth and claws that suggest they were meat-eaters.

At least five Tawa specimens were found together in the Hayden Quarry on the Ghost Ranch, Abiquiu, once the retreat of American artist Georgia O'Keefe. One specimen is a near-complete skeleton of a juvenile — which stood 70 centimetres high at the hips and was about two metres long. There is also another larger, near-complete skeleton, thought to be an adult.

Quality find

The first Tawa was found in 2004, when people attending a seminar at the Ruth Hall Museum of Paleontology in Abiquiu were on a hike in the region and found protruding remains of the dinosaur. A team of four graduate students studying with the museum's curator, Alex Downs, then excavated the fossils.

{{The hills of Ghost Ranch, New Mexico - home of the Tawa specimens.}
Sterling Nesbit}

tThe specimens were miraculously pristine, with most of the bones still in a natural three-dimensional form, not crushed like typical fossils of their age. This also allowed for better identification of the air sacs in the vertebrae, a feature typical of theropods. Team members are still trying to work out the function of these cavities — which are like those found in today's birds, relatives of theropods.

Surmising that the Tawa individuals probably died and were quickly buried, says Nathan Smith, a co-author from the Field Museum in Chicago. "We were lucky to find skeletons nearly intact."

Randall Irmis, a palaeontologist at the University of Utah in Salt Lake City and co-author of the study, says that their conclusions about the migration patterns are supported by the presence in the Hayden Quarry of multiple dinosaur species known to have originated much farther south.

"We think all the major dinosaur groups had the ability to get to [what is now] North America during the late Triassic," says Irmis. "Only the carnivorous dinosaurs found the North American climate to be hospitable."

Migratory origins

An important aspect of Tawa's discovery is the context it provides for a long-debated, mysterious specimen from South America, called Herrerasaurus ischigualastensis. First identified in southern Brazil by the Argentinian palaeontologist Osvaldo Reig, H. ischigualastensis had a mosaic of traits that meant it was difficult to define as a theropod, or even to be sure it was a dinosaur. It had the typical carnivore traits, but no air sacs in its bones, according to later reports on more defined specimens from Argentina2. But other similarities with Tawa mark out H. ischigualastensis as a theropod, says Nesbitt.

Kevin Padian, a palaeontologist at the University of California, Berkeley, who mentored both Nesbitt and Irmis and who has long argued that H. ischigualastensis may not be a theropod, isn't convinced. "I'm not disagreeing on Tawa — it's a great step — but the book is not closed," he says, adding that he is looking for more primitive creatures to settle the question.

Researchers expect a renewed hunt for the first dinosaurs — a trail likely to go to the Valley of the Moon in the province of San Juan, Argentina, the area where the oldest dinosaur fossils to date have been found.

References
1. Nesbitt, S. J. et al. Science 326, 1530-1533 (2009). | Article | ChemPort |
2. Sereno, P. C. & Novas, F. E. Science 258, 1137-1140 (1992). | Article | PubMed


[naturenews]
Published online 10 December 2009 | Nature | doi:10.1038/news.2009.1135
News
Ovaries reveal their inner testes
Knocking out a single gene transforms gonads in mice.
Brendan Borrell
{{A mouse with some very confused ovaries}
.Getty}

Inside every ovary lurks a testicle just waiting to develop. So says a study in mice that further overturns traditional views of sexual development — and reveals that females must constantly suppress their masculine side.

Mathias Treier, a geneticist at the European Molecular Biology Laboratory in Heidelberg, Germany, and his colleagues deleted a gene called FOXL2 in sexually mature mouse ovaries. When they examined the ovaries three weeks later, they had switched sex and started pumping out the hormone testosterone.

"The major finding is that females must actively suppress the male pathway inside the ovary," Treier says. "Here is a gene that is not located on the sex chromosome that makes you stay female."

In many mammals, sex is determined during the early development of the fetus by the activity of a gene called SRY located on the Y sex chromosome, carried only by males. That gene triggers a second gene, called SOX9, which induces testes development.

But Treier's team have found that FOXL2 is a key 'power broker', acting in conjunction with the cell's oestrogen receptor in order to inhibit SOX9 in adult females and preventing the ovaries from producing testosterone. The study is published this week in Cell¹.

Sex change

This study is not the first to transform adult ovaries into testes. In work published in 1999 in Science, John Couse, then at the US National Institute of Environmental Health Sciences in North Carolina, and his colleagues knocked out both types of oestrogen receptor in mice and found that the gonads showed signs of changing sex, but they did not produce testosterone². High levels of oestrogen can also trigger sex changes in a number of animals, including marsupial mammals.

But the finding that ovaries must actually strive to keep their identity makes this "a very exciting piece of work", says Richard Anderson, a reproductive endocrinologist at the Queen's Medical Research Institute at the University of Edinburgh, UK, who has studied FOXL2. "What they are proposing is that the ovary is not a fixed structure but must maintain its 'ovary-ness'," he says.

Treier had expected to achieve sex reversal in the mice by knocking out FOXL2 early in sexual development, rather than having to wait until the mice were mature. He was puzzled to find that knocking out the gene in immature mice stopped the ovaries from developing properly and led to their degeneration. He says that it has taken his group ten years to understand the gene's true role in sex determination.

Treier believes that FOXL2 could be one of the oldest sex-determining genes in vertebrates. For example, it is known that female goats that are missing the section of chromosome containing FOXL2 develop as males. Regulation of the gene may also enable female fish to change sex after sexual development, and FOXL2 could underlie the masculinization seen in some menopausal women, Treier says.

Because the ovarian cells that give rise to eggs were not modified by the gene deletion, Treier's transsexual mice could not make sperm. The next step, he says, is to add sperm stem cells to these modified ovaries to see if they can produce sperm. "It's outlandish, and the chance that it will work is very small," he says. "But you never know."

References
1. Uhlenhaut, N. H. et al. Cell 139, 1130-1142 (2009).
2. Couse, J. F. et al. Science 286, 2328-2331 (1999). | Article

news20091211nn1

[naturenews] from [nature.com]

[naturenews]
Published online 10 December 2009 | Nature | doi:10.1038/news.2009.1137
News
Dinosaurs diversified before spreading around the world
Fossil finds suggest that South America was the wellspring of the dinosaurs.
Rex Dalton

Fossils found in the US state of New Mexico are providing strong evidence that dinosaurs originated in what is now South America, and had already evolved into three main groups before spreading around the world.

The fossils — of a new species, named Tawa hallae — back more than 200 million years, to when Earth's land masses were joined together as the supercontinent Pangaea. They retain features from the earliest dinosaur specimens, found in South America.

Dinosaurs are thought to have first evolved about 230 million years ago, their populations yo-yoing until a cataclysmic event wiped them out about 65 million years ago.

The find suggests that the early dinosaurs — classified as theropods, sauropods and ornithischians — migrated from South America around the rest of Pangaea roughly 220 million years ago. The animals then settled in the most suitable climates at different latitudes, says palaeontologist Sterling Nesbitt, of the University of Texas at Austin, who led the study.

Nicknamed Tawa, the two-legged creature studied by Nesbitt's team lived about 215 million years ago, and shares key features with the earliest known theropods, including air sacs in bones, hips with open sockets, and teeth and claws that suggest they were meat-eaters.

At least five Tawa specimens were found together in the Hayden Quarry on the Ghost Ranch, Abiquiu, once the retreat of American artist Georgia O'Keefe. One specimen is a near-complete skeleton of a juvenile — which stood 70 centimetres high at the hips and was about two metres long. There is also another larger, near-complete skeleton, thought to be an adult.

Quality find

The first Tawa was found in 2004, when people attending a seminar at the Ruth Hall Museum of Paleontology in Abiquiu were on a hike in the region and found protruding remains of the dinosaur. A team of four graduate students studying with the museum's curator, Alex Downs, then excavated the fossils.

{{The hills of Ghost Ranch, New Mexico - home of the Tawa specimens.}
Sterling Nesbit}

tThe specimens were miraculously pristine, with most of the bones still in a natural three-dimensional form, not crushed like typical fossils of their age. This also allowed for better identification of the air sacs in the vertebrae, a feature typical of theropods. Team members are still trying to work out the function of these cavities — which are like those found in today's birds, relatives of theropods.

Surmising that the Tawa individuals probably died and were quickly buried, says Nathan Smith, a co-author from the Field Museum in Chicago. "We were lucky to find skeletons nearly intact."

Randall Irmis, a palaeontologist at the University of Utah in Salt Lake City and co-author of the study, says that their conclusions about the migration patterns are supported by the presence in the Hayden Quarry of multiple dinosaur species known to have originated much farther south.

"We think all the major dinosaur groups had the ability to get to [what is now] North America during the late Triassic," says Irmis. "Only the carnivorous dinosaurs found the North American climate to be hospitable."

Migratory origins

An important aspect of Tawa's discovery is the context it provides for a long-debated, mysterious specimen from South America, called Herrerasaurus ischigualastensis. First identified in southern Brazil by the Argentinian palaeontologist Osvaldo Reig, H. ischigualastensis had a mosaic of traits that meant it was difficult to define as a theropod, or even to be sure it was a dinosaur. It had the typical carnivore traits, but no air sacs in its bones, according to later reports on more defined specimens from Argentina2. But other similarities with Tawa mark out H. ischigualastensis as a theropod, says Nesbitt.

Kevin Padian, a palaeontologist at the University of California, Berkeley, who mentored both Nesbitt and Irmis and who has long argued that H. ischigualastensis may not be a theropod, isn't convinced. "I'm not disagreeing on Tawa — it's a great step — but the book is not closed," he says, adding that he is looking for more primitive creatures to settle the question.

Researchers expect a renewed hunt for the first dinosaurs — a trail likely to go to the Valley of the Moon in the province of San Juan, Argentina, the area where the oldest dinosaur fossils to date have been found.

References
1. Nesbitt, S. J. et al. Science 326, 1530-1533 (2009). | Article | ChemPort |
2. Sereno, P. C. & Novas, F. E. Science 258, 1137-1140 (1992). | Article | PubMed

news20091211nn2

[naturenews] from [nature.com]

[naturenews]
Published online 10 December 2009 | Nature | doi:10.1038/news.2009.1139
News
Asia populated in one migratory swoop
Large genetic study brings message of ancestral unity.
David Cyranoski

{{Negrito populations in Malaysia are more closely related to other Asians than previously thought}
.F. Grehan/CORBIS}

Researchers mapping a massive array of genomes across Asia say they have found evidence that humans covered the continent in a single migratory wave, and share a common ancestry1.

The findings were released by the Human Genome Organisation (HUGO) Pan-Asian SNP Consortium which looks at single-nucleotide polymorphisms (SNPs), or variations at individual bases that make up the genetic code. The results challenge the view that Asia was populated by at least two waves of migration.

"In Asia, we are all related," says Edison Liu, a lead author from the Genome Institute of Singapore. "It brings us closer together."

It is thought that a wave of humans emerged from Africa some 60,000–75,000 years ago and travelled along the southern coast of India, into southeast Asia and down to Oceania. But scientists struggled to explain some of the variation seen in Asia today — such as the obvious physical differences between Malaysian and Filipino Negrito populations and other Asians. Some researchers have postulated that a second wave, or series of waves, from a northern route largely repopulated the area, leaving the Negrito and others as relicts of the earlier migration.

The new study, a five-year examination of variation at some 55,000 SNPs in 1928 individuals, found that Negrito populations had a high level of genetic overlap with other southeast Asia populations, suggesting a common ancestry. East Asians, the analysis suggests, share a large degree of common genetic background with southeast Asians but very little with central Asians, seeming to preclude a peopling of east Asia through a northern route via the Eurasian Steppes. And genetic variation within local populations decreased from southeast to northeast Asia. The two observations suggest that diverse peoples living in southeast Asia migrated northwards.

"It's an impressive collection of samples, a huge amount of work and analysis, and it will contribute greatly to the field," says Mark Stoneking, an evolutionary geneticist at Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was not involved in the study.

Asian unity

Merely organizing the work was a massive task. Researchers in 11 countries and regions took samples from 73 populations, requiring countries often at political or economic loggerheads to share ideas, technology and genomes. For countries lacking the technological capabilities to do the genetic analysis but loath to ship genetic samples to another country, Liu established a system by which researchers could bring the samples to host countries and do the studies themselves, in collaboration with their hosts. "The chain of custody was never broken," he says. "It was extraordinarily collegial."

The result is not a complete shock. While this study provides the most detailed analysis of genetic diversity among Asians to date, a 2005 study on mitochondrial DNA came to a similar conclusion². Martin Richards, at the University of Leeds, UK, is a specialist in genetic variation in southeast Asia who led that study. "By and large, [the new study] is not surprising for fans of mitochondrial DNA, I think, but naturally it is very heart-warming," he says.

The new study also supports mitochondrial DNA evidence that challenges the customary "out of Taiwan" model, in which migration from mainland China through Taiwan led to the settlement of southeast Asia and the Pacific islands. Instead it seems Taiwan may have been largely settled from islands in southeast Asia.

But the results are not conclusive, as the authors admit. Stoneking says he was "very surprised that the Negrito populations were not more genetically distinct", and would like to see other supposed relict populations, such as those in New Guinea and Australia, studied in the same kind of detail. He argues that it is not possible to tell whether extensive genetic intermingling with surrounding populations might have obscured evidence for two waves of migration. He says he has evidence to support the two-wave theory in work yet to be published that looks specifically at mitochondrial DNA and Y-chromosomes of Negrito populations.

Liu says he is discussing plans for a second phase study with much higher resolution — based on 600,000–1 million SNPs. Possible extensions for the new project will be a look at copy number variation (duplications in sections of DNA), a resequencing of mitochondrial DNA and a focus on specific genetic components such as differences between enzymes that metabolize drugs, and human leukocyte antigen variations. It will be especially tantalizing, says Liu, to see if drug-metabolism genes show the same north–south variation in east Asia. "There would be implications for drug response and clinical trials," he says – although he adds that it will not be possible to link specific health information to genotypes across the continent.

References
1. The HUGO Pan-Asian SNP Consortium Science 326, 1541-1545 (2009). | Article | ChemPort |
2. Macaulay, V. et al. Science 308, 1034-1036 (2005). | Article | PubMed | ChemPort |