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jueves, 19 de febrero de 2009

Museum Secrets Unmasked by "Museomics" Technologies


Brian Handwerk

In museum display cases and dusty drawers worldwide, a burst of new technologies is now unlocking otherwise hidden secrets from fossils, fur, and other relics of a vanished past.

The phenomenon, called museomics, gives new life to musty old objects.

Stephan Schuster, a molecular biologist and biochemist at Pennsylvania State University, coined the term. With colleague Webb Miller, Schuster last year reconstructed most of the mammoth genome using hair that had been sitting in a Russian museum for 200 years.

"No effort was made to freeze it or dry it. It's just hair in a drawer. And [our attempts to recover DNA] worked. This is what gave us the idea for trying to attempt something like museomics," Schuster said.

(Related: "Mammoth Genome Decoded—Clones on the Way?")

"We say, take the effort and look for feathers, horns, hooves, eggshells, you name it. I think what we tried to show is that whatever is in a museum, it's worth taking the effort to go in and look at it systematically."

Warning Signs

Schuster and Miller also studied the Tasmanian tiger, or thylacine, a doglike marsupial extinct since the mid-1930s.

The pair used DNA sequencing technology to search for causes of the animal's demise by analyzing preserved specimens, including a century-old thylacine from the National Zoo in Washington, D.C., and another that died in the London Zoo in 1893.

"One of the striking results was how genetically similar those two individuals were," Schuster said. "They exhibit a lack of genetic diversity, which signals a species on the brink of extinction."

Such genetic warning signs could help scientists identify threats to modern species and possibly prevent extinctions.

Help for Healers

Medical researchers are also using new techniques to comb museum collections for information that can promote human health.

The Mütter Museum at the College of Physicians of Philadelphia is renowned for its unique group of pathological and anatomical specimens.

Curator Anna Dhody said a Canadian team is trying to extract a cholera strain's DNA from "wet" specimens—human intestines floating in preservative solutions that are a century and a half old.

"The DNA in those is rendered null and void traditionally about three days after it makes contact with the solution, previously formaldehyde and now alcohol," she explained.

The research might produce a genetic and physical map of cholera epidemics that could become a valuable weapon in the ongoing fight against the disease.

Robert Hicks, director of the museum, noted that the Mütter's collection of extensively documented U.S. Civil War wounds could help doctors save the lives of soldiers in global conflict zones such as Iraq and Afghanistan.

"Civil War injuries were quite traumatic," he said. Minie balls, the huge lead bullets used back then, "took away large areas of tissue and bone—they were horribly disfiguring injuries."

Such injuries are similar to those caused by the homemade weapons used in recent warfare, prompting battlefield surgeons to take a closer look at historic Civil War injuries.

"The documentation of these injuries is now of great relevance, and I'm hoping that we can help make more of those connections," Hicks said.

Use It, Don't Lose It

At New York's American Museum of Natural History, Nancy Simmons, curator of the department of mammalogy, says she gets many more requests for DNA sampling than when she began overseeing the museum's 280,000-odd mammal specimens two decades ago.

"They want to get little clips of skin or drill into bones for DNA analyses or oxygen isotope analyses and things like that," said Simmons, curator of the mammalogy department.

"You can't get samples of all the species and populations in the world, and no one has the time or money to go to all the places where these animals live," she explained.

The museum's humpback whale collection, for example, offers scientists a peek into the past population structures before the great mammals were heavily hunted.

"By looking at baleen from the 1800s, one researcher found that whole maternal lineages have been exterminated," Simmons said.

Simmons noted that her mission is to protect the specimens in her care, and research always carries a risk of slowly degrading irreplaceable objects.

"We walk a fine line," she said. "We don't want to waste material or see things damaged or destroyed, but we want to encourage use of the collection. Otherwise it's like having a library and not letting anyone read the books."

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