Monday, March 24, 2008

New Zealand's 'Living Dinosaur' -- The Tuatara -- Is Surprisingly The Fastest Evolving Animal

In a study of New Zealand's "living dinosaur" the tuatara, evolutionary biologist, and ancient DNA expert, Professor David Lambert and his team from the Allan Wilson Centre for Molecular Ecology and Evolution recovered DNA sequences from the bones of ancient tuatara, which are up to 8000 years old. They found that, although tuatara have remained largely physically unchanged over very long periods of evolution, they are evolving - at a DNA level - faster than any other animal yet examined.

"What we found is that the tuatara has the highest molecular evolutionary rate that anyone has measured," Professor Lambert says.

The rate of evolution for Adélie penguins, which Professor Lambert and his team have studied in the Antarctic for many years, is slightly slower than that of the tuatara. The tuatara rate is significantly faster than for animals including the cave bear, lion, ox and horse.

"Of course we would have expected that the tuatara, which does everything slowly -- they grow slowly, reproduce slowly and have a very slow metabolism -- would have evolved slowly. In fact, at the DNA level, they evolve extremely quickly, which supports a hypothesis proposed by the evolutionary biologist Allan Wilson, who suggested that the rate of molecular evolution was uncoupled from the rate of morphological evolution."

Allan Wilson was a pioneer of molecular evolution. His ideas were controversial when introduced 40 years ago, but this new research supports them.

Professor Lambert says the finding will be helpful in terms of future study and conservation of the tuatara, and the team now hopes to extend the work to look at the evolution of other animal species.

"We want to go on and measure the rate of molecular evolution for humans, as well as doing more work with moa and Antarctic fish to see if rates of DNA change are uncoupled in these species. There are human mummies in the Andes and some very good samples in Siberia where we have some collaborators, so we are hopeful we will be able to measure the rate of human evolution in these animals too."

The tuatara, Sphendon punctatus, is found only in New Zealand and is the only surviving member of a distinct reptilian order Sphehodontia that lived alongside early dinosaurs and separated from other reptiles 200 million years ago in the Upper Triassic period.

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Looks Like Jello, Works Like Cartilage

Replacement Part?
Replacement Part?

March 21, 2008 -- It may not look like much, but a slippery, Jello-like material developed by scientists in the United States and Japan could soon be improving everything from artificial joints to contact lenses.

The material is a hydrogel, and as the name implies, is made mostly of water. But it's also surprisingly resilient.

"Most hydrogels are like gelatin; you touch them and they break into pieces," said Wen-li Wu, a scientist at the National Institute of Standards and Technology and an author of the new study.

"What we are talking about is a gel that you can squeeze as hard as you can, but it's still slippery," he said.

Produced from materials that are cheap and readily available, the hydrogel is held together by two polymers. The first is a charged solid that clings to a second, uncharged liquid polymer. If a crack develops in the solid polymer, the liquid polymer flows into the defect and essentially heals it.

The hydrogel is clear and as slippery as natural cartilage -- an improvement over current materials used in artificial joints. The hydrogel is also softer and more resistant to wear than current materials, say its makers.

"It will definitely absorb more shocks than current materials," said Wu.

The research builds on a 2003 study from the lab of study collaborator Jian-Ping Gong at Hokkaido University in Japan.

Since it is resistant to the build-up of proteins, the hydrogel could also be used for contact lenses and artificial corneas, among other applications.

Studies in animals have proved promising, but there are currently no clinical trials underway to evaluate the hydrogel's use in humans.

"It's an excellent material, very tough," said Curt Frank, a scientist at Stanford University who works on hydrogels but was not involved in the NIST work.

"The hydrogel's properties are very comparable to human tissues and have the potential to create a device that could replace human tissue," he said.

The research was presented at the March meeting of the American Physical Society.

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Cloning treats mouse Parkinson's

Brain showing the area affected by Parkinson's disease
Parkinson's disease affects cells in the brain
Therapeutic cloning has been successfully used to treat Parkinson's disease in mice, US researchers say.

The study in Nature Medicine provides the best evidence so far that the controversial technique could one day help people with the condition.

The Memorial Sloan-Kettering Cancer Centre team say it is the first time animals have been successfully treated with their own cloned cells.

UK experts said the work was promising and exciting development.

No rejection

In Parkinson's disease, nerve cells in the part of the brain that controls muscle movement either die or become impaired.

Normally, these cells produce a vital chemical known as dopamine, which allows smooth, co-ordinated function of the body's muscles and movement.

This is an exciting development, as for the first time, we can see that it may be possible to create a person's own embryonic stem cells to potentially treat their Parkinson's
Dr Kieran Breen, Parkinson's Disease Society
In therapeutic cloning, the nucleus of a cell is inserted into an egg with the nucleus removed.

This cell then develops into an embryo from which stem cells can be harvested and used as a treatment.

In this study, stem cells were developed into dopamine-producing neurons the missing nerve cells in Parkinson's disease.

The mice that received neurons derived from their own clones showed significant signs of improvement.

But when these neurons were grafted into mice that did not genetically match the transplanted cells, the cells did not survive and the mice did not recover.

The researchers say the therapy is promising because, as the cells originally came from the animal that was ill, they were not rejected by its immune system.

'Great hope'

Scientists are pursuing the use of stem cell therapy for Parkinson's disease because it would allow the replacement of the dead dopamine-producing nerve cells with new, healthy cells.

This should restore the supply of dopamine within the brain and allow it to work normally again.

However, the challenge has been to produce nerve cells which can survive after transplantation.

Dr Kieran Breen, director of research and development at the Parkinson's Disease Society said: "This is an exciting development, as for the first time, we can see that it may be possible to create a person's own embryonic stem cells to potentially treat their Parkinson's.

"Researchers in this area now need to carry out more studies to satisfy safety concerns and to make the process more efficient before these studies are carried out on people living with Parkinson's."

He added: "Stem cell therapy offers great hope for repairing the brain in people with Parkinson's.

"It may ultimately offer a cure, allowing people to lead a life that is free from the symptoms of Parkinson's."

Professor Robin Lovell-Badge, an expert in stem cell research at the National Institute of Medical Research, said this was good research which showed using therapeutic cloning could be beneficial.

"There was a very significant level of recovery.

But he added: "They only studied the mice for 11 weeks afterwards, which is not a huge amount of time to see how persistent the repaid would be."

However, the experts said much more research in both animals and humans was needed before the treatment could be offered to people with Parkinson's.

In a separate study, a team from University College London have discovered mutations in a gene which may trigger Parkinson's in people with a family history of the condition.

The finding could provide scientists with a clue as to what causes Parkinson's - and could contribute to the search for new treatments.

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Since '01, Guarding Species Is Harder

A black-tailed prairie dog feeds in Kansas's Logan County in this file photo from 2006. A Western conservation group is suing the federal government to force it to respond to a petition to list the animal as endangered. (By Steven Hausler -- Associated Press)

With little-noticed procedural and policy moves over several years, Bush administration officials have made it substantially more difficult to designate domestic animals and plants for protection under the Endangered Species Act.

Controversies have occasionally flared over Interior Department officials who regularly overruled rank-and-file agency scientists' recommendations to list new species, but internal documents also suggest that pervasive bureaucratic obstacles were erected to limit the number of species protected under one of the nation's best-known environmental laws.

The documents show that personnel were barred from using information in agency files that might support new listings, and that senior officials repeatedly dismissed the views of scientific advisers as President Bush's appointees either rejected putting imperiled plants and animals on the list or sought to remove this federal protection.

Officials also changed the way species are evaluated under the 35-year-old law -- by considering only where they live now, as opposed to where they used to exist -- and put decisions on other species in limbo by blocking citizen petitions that create legal deadlines.

As a result, listings plummeted. During Bush's more than seven years as president, his administration has placed 59 domestic species on the endangered list, almost the exact number that his father listed during each of his four years in office. Interior Secretary Dirk Kempthorne has not declared a single native species as threatened or endangered since he was appointed nearly two years ago.

In a sign of how contentious the issue has become, the advocacy group WildEarth Guardians filed a lawsuit Wednesday seeking a court order to protect 681 Western species all at once, on the grounds that further delay would violate the law. Among the species cited are tiny snails, vibrant butterflies, and a wide assortment of plants and other creatures.

"It's an urgent situation, and something has to be done," said Nicole Rosmarino, the group's conservation director. "This roadblock to listing under the Bush administration is criminal."

Developers, farmers and other business interests frequently resist decisions on listing because they require a complex regulatory process that can make it difficult to develop land that is home to protected species. Environmentalists have also sparred for years with federal officials over implementation of the law.

Nevertheless, Presidents George H.W. Bush and Bill Clinton added an average of 58 and 62 species to the list each year, respectively.

One consequence is that the current administration has the most emergency listings, which are issued when a species is on the very brink of extinction.

And some species have vanished. The Lake Sammamish kokanee, a landlocked sockeye salmon, went extinct in 2001 after being denied an emergency listing, and genetically pure Columbia Basin pygmy rabbits disappeared last year after Interior declined to protect critical habitat for the species.

Administration officials -- who estimate that more than 280 domestic species should be on the list but have been "precluded" because of more pressing priorities -- do not dispute that they have moved slowly, but they dispute the reasons.

Bush officials say they are struggling to cope with an onslaught of litigation, but internal documents and several court rulings have revealed steps the administration has taken to make it harder, and slower, to approve listings.

Fish and Wildlife Service Director Dale Hall said his agency, which decides on most proposed listings of endangered species and their critical habitat, has been hamstrung by a slew of lawsuits and has just begun to dig out. He told the House Appropriations interior subcommittee last month that his agency will make decisions about 71 species by Oct. 1 and an additional 21 species a year later.

"Lawsuits, starting in the early '90s, have really driven things," Hall said, adding that the administration has tried to keep species from declining to the point where they need to be listed. "I'm feeling pretty good we're back on track to do the job the way it's supposed to be done."

In court cases, however, a number of judges have rejected decisions made by Hall's agency and have criticized its slow pace. On March 5, a U.S. district judge in Phoenix ordered Interior to redesignate bald eagles in Arizona's Sonoran Desert as threatened after the agency delisted the entire species last summer.

Three weeks before Interior officials rejected a petition to keep the desert eagles listed, a scientific advisory panel it convened wrote that the population "appears to be less viable than populations in other parts of the country" because it had fewer than 50 nesting pairs. Survival usually requires 500 breeding pairs.

The Fish and Wildlife Service never released that report, along with internal agency documents showing "substantial" evidence that the Arizona eagles should be kept on the list: Both the report and the documents were unearthed under the Freedom of Information Act by the Center for Biological Diversity, an advocacy group.

In another case, Judge William Alsup of the U.S. District Court for the Northern District of California ruled in late January that Interior violated the law when it did not act on 55 endangered and threatened foreign species that the department had described as qualified to be listed. The department has listed six foreign species during Bush's term.

"If the Service were allowed to continue at its current rate, it is hard to imagine anytime in the near or distant future when these species will be entitled to listing," the judge wrote. "Such delay hardly qualifies as 'expeditious progress' and conflicts with the purpose of the ESA to provide 'prompt action' [if there is] substantial scientific evidence that the species is endangered or threatened."

At NatureServe, a private nonprofit that does independent scientific assessments that the government often uses in crafting conservation policy, Vice President and Chief Scientist Bruce Stein said the decline in listings has been "dramatic. . . . It shows a shift in both funding and policy priorities."

In one such shift, senior Interior officials revised a longstanding policy that rated the threat to various species based primarily on their populations within U.S. borders. They then argued that species such as the wolverine and the jaguar do not need protection because they also exist in Canada or Mexico.

In another policy reversal, Interior's solicitor declared in a memo dated March 16, 2007, that when officials consider whether a significant portion of a species' range is in peril, that "phrase refers to the range in which a species currently exists, not to the historical range of the species where it once existed." The memo added that the Interior secretary "has broad discretion" in defining what is "significant."

For a two-year period, Fish and Wildlife also said that if the agency identified a species as a candidate for the list, citizens could not file petitions for that species, effectively eliminating any legal deadlines. The result, said Kieran Suckling, head of the Center for Biological Diversity, was to create "endangered species purgatory." In 2003, U.S. District Judge Reggie B. Walton overturned the policy on the grounds that it allowed the agency to "avoid their mandatory, non-discretionary duties to issue findings" under the act.

In addition, the agency limited the information it used in ruling on the 90-day citizens' petitions that lead to most listings. In May 2005, Fish and Wildlife decreed that its files on proposed listings should include only evidence from the petitions and any information in agency records that could undercut, rather than support, a decision to list a species.

Unsigned notes handwritten on May 16, 2005, by an agency official, obtained under the Freedom of Information Act, attributed the policy to Douglas Krofta, who heads the Endangered Species Program's listing branch. The notes said employees "can use info from files that refutes petitions but not anything that supports, per Doug."

Hall said the agency abandoned that policy in late 2006, but he issued a memo in June 2006 that mirrors elements of it, stating, "The information within the Service's files is not to be used to augment a 'weak' petition."

As listings have slowed, lawsuits challenging the administration's practices have skyrocketed, according to the biodiversity center, which specializes in endangered-species issues. There have been 369 listing-related suits against Bush, compared with 184 against Clinton. "The Bush administration has effectively killed the listing program," said Suckling, whose group's petitions and suits have driven 92 percent of the listings under Bush.

The Justice Department would not release figures on how the government has fared defending endangered species suits or how much it has cost taxpayers. Officials acknowledge they have not done well in the courts: Hall said he is frustrated that judges demand a higher burden of scientific proof to deny a listing or to take a species off the list than to list a species.

Since 2001, Jay Tutchton, general counsel for WildEarth Guardians, has filed 25 suits seeking listings and critical habitat designations for 45 species for several clients. He has won every time.

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