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Our World — 29 September 2007


Straight ahead on "Our World" ... Plucking DNA samples from the hair of extinct animals ... the health benefits of drinking tea ... and deformed frogs, parasites, and the environment ...

JOHNSON: "So we know that parasites can often kill large numbers of frogs, but what the long-term consequences of that are for amphibian population declines still remains largely unexplored."

Those stories, a Space Age anniversary, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Recreating dinosaurs and other long-extinct species from their DNA is the stuff of science fiction, but ancient DNA may be easier to recover and study thanks to new research published this week. An international science team was able to unlock the genetic blueprint of extinct Siberian woolly mammoths from samples of their hair, using a technique that is easier and cheaper than extracting the DNA from bone. VOA's Jessica Berman reports.

BERMAN: Scientists mapped the entire DNA sequence from the hair shafts of 13 Siberian woolly mammoths.

The mammoths roamed the earth 30,000 to 60,000 years ago and are the common, prehistoric ancestor of the African and Indian elephants.

The hair in the study was obtained from a frozen mammoth found in 1799 in the permafrost near Siberia.

For the past 200 years, the hair remains were stored at room temperature at the Zoological Museum in St. Petersburg.

Stephan Shuster is with the Center for Comparative Genomics at Pennsylvania State University.

Shuster, who is part of the international team that sequenced the genetic material taken from the hair samples, says no one thought it was possible to derive usable DNA.

SHUSTER: "All of us would have predicted that just the fact that ... it was not kept frozen or at least refrigerated would have destroyed every remaining DNA that was in that bone or in that hair. But in our study we can show, no, this old one worked, not only worked, but in this smallest amount of hair that we had."

BERMAN: Shuster says it is possible to obtain DNA from dinosaur bones. That is how paleontologists know as much as they do about the age of the creatures and their evolutionary history.

But he says DNA analysis of dinosaur bones is expensive and difficult. DNA analysis of hair, on the other hand, is quite simple and relatively inexpensive, according to Shuster.

SHUSTER: "It is kind of like a biological plastic. And the contaminating bacteria and fungi is sitting on the outside of the hair. And so, we can bleach, like in the laundry machine, we can bleach the outside of the hair, and the DNA on the inside stays intact. And so after we remove the contaminating bacteria, we then dissolve the bacteria from the hair and then isolate very pure mammoth DNA from it."

Shuster says the hair analysis can be performed on samples as small as a single strand. And he says researchers found usable DNA along the entire hair shaft, not just the hair root closest to the mammoth's skin.

Shuster expects the finding will tell researchers a lot about the evolution of elephants.

SHUSTER: "This gives you a very good time for determining the time that the living elephant, the Indian elephant and the African elephant, how long it took them before they separated and the last common ancestor of the two."

BERMAN: The study describing DNA analysis of woolly mammoth hair is published in the journal Science. Jessica Berman, VOA News, Washington.

We humans like to think of ourselves as vastly superior to the rest of the animal kingdom, but in a lot of very basic ways, we're really not so different. For example, the way we choose a mate. Social position, physical appearance, intelligence are part of it. And now, as we hear from health reporter Rose Hoban, new research indicates that humans may prefer partners with certain vocal qualities.

HOBAN: Harvard University Anthropologist Coren Apicella spent time living with and studying a small tribe in Tanzania called the Hadza.

APICELLA: "This is one of the last hunter-gatherer populations that practiced traditional foraging and hunting techniques that are left on the planet. And they're really great to study because they provide sort of a window to our past. They live just like we would have lived, our ancestors would have lived about 200,000 years ago."

HOBAN: The Hadza do not use any form of modern birth control, so Apicella says they're a good population to study if you want to look at the reproductive outcomes of certain behaviors. She recorded the voices of about 50 men and 50 women and then questioned all of them about their reproductive histories.

APICELLA: "And we found that men who have deeper voices have more babies, and they have more surviving children as well."

HOBAN: Apicella says it's not clear why the deeper-voiced men were so much more successful at reproducing.

APICELLA: "It may have something to do with maybe they have greater access to mates, and therefore they're able to have more children or perhaps maybe it has something to do with testosterone, these men who have lower pitched voices have higher levels of testosterone, perhaps it makes them better hunters and they're able to bring home more food to their families. And therefore their wives perhaps have shorter inter-birth intervals and can resume ovulation more quickly, and therefore they have more children. Or it could be, you know, maybe they start reproducing at an earlier age, and they sort of get a head start."

HOBAN: And Apicella reports, the women were more attracted to the men with lower pitched voices.

APICELLA: "Women actually perceived men that had deeper pitched voices to be better hunters."

HOBAN: Apicella suggests that over the millennia, these innate preferences gave men with lower pitched voices an evolutionary advantage — they mated more often and more successfully, and therefore the trait for low-pitched voice was preferentially handed from generation to generation. Vocal quality was not a one-way preference. Hadza men found women with higher-pitched voices to be more feminine, and more beautiful.

Apicella's study is published in the journal Biology Letters. I'm Rose Hoban.

Tea is said to be the second most widely consumed beverage in the world, behind plain water. It's been part of our diet for thousands of years, and in various forms and varieties has been enjoyed in probably every country on Earth.

The U.S. Department of Agriculture this month hosted a scientific forum on the health benefits of tea, which, researchers say, are considerable. In fact, as co-chair Jeffrey Blumberg of Tufts University pointed out, there has been a virtual explosion of research on the subject.

BLUMBERG: "Over 900 articles were published in each of the last two years in the peer-reviewed scientific literature directed toward the benefits of drinking tea on health."

As a natural product, tea is a complex mix of molecules, and scientists are learning how they affect the body. One of them, an amino acid called theanine, is found almost exclusively in many varieties of tea. Researchers are discovering that it affects the brain's alpha wave activity, increasing both calmness and alertness. John Foxe of the City University of New York is among the scientists investigating how theanine works, which may be in combination with other components of tea.

FOXE: "So one possibility is that theanine will interact with the other major psychoactive compound that you're all highly familiar with, caffeine. And what I can tell you there is that it's a highly synergistic effect. So if we see a small change with theanine and a small change with caffeine, you put the two things together [and] you get a mighty change in the system."

What else is tea good for? Well, according to the scientists at the symposium on tea and health, there are things in tea that may improve blood vessel function, help you lose weight through changes in metabolism, and possibly reduce the risk of cancer through antioxidants called flavonoids.

And researcher Dr. Sylvia Mandel of the Eve Topf Center for Neurodegenerative Diseases in Israel says some of the components of tea, especially green tea, may have medicinal qualities.

MANDEL: "We now consider green tea, or green tea polyphenals, as multi-functional drugs. So we believe that green tea polyphenals might have potential [to] treat neurodegenerative diseases. We think maybe the polyphenal by itself is not sufficient to induce these protective effects, but a combination, a cocktail of drugs might be even more potent to treat Parkinson's Disease or Alzheimer's Disease."

When new medicines are developed, regulators want to see proof that they're effective, of course, but also that they're safe. Nutrition researcher Lenore Arab of Tufts University says that with a record going back to antiquity, tea's safety is well known.

ARAB: "What we've got in those 4,000 years of experiments, however, is a lot of proof about its safety. And now what we're able to do is very good research on what might there be above and beyond this that is beneficial."

Dr. Lenore Arab at this month's international symposium on tea and health in Washington. She also pointed out that recent research has shown that tea seems to have a protective effect against cardiovascular disease, including stroke, and that the protective effect increases the more tea you drink.

Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

This week, a place to go for news and comment from the art world — not just painting and sculpture, but dance, theater, music and publishing from a variety of sources, all collected in one convenient place.

McLENNAN: " is the largest aggregator of arts news on the Internet. We look at about 200 publications worldwide every day and pull out the stories that we think are the most interesting."

Doug McLennan is the editor of, which is celebrating its eighth birthday this month. McLennan, a former arts critic for a Seattle newspaper, got the idea when he was browsing another newspaper website and stumbled on a weeks-old story that he had entirely missed.

McLENNAN: "And that kind of gave me the idea that there were probably a lot of stories in papers around the country, around the world, that people who were interested in the arts would want to see. In effect you could put together a pretty great arts section by pointing out what was the best of the best."

And it's not just arts news, but also a collection of blogs, offering comment and opinion on a wide range of topics from books to the business of art.

McLENNAN: "I think publications that don't try to give you a strong point of view are not as interesting as those which say, hey you know, there's a lot of stuff out there, but this is what I or we personally think is the most interesting. And it's a way of giving context and form and understanding about what the world looks like."

There are also videos, and Doug McLennan says he plans to add more multimedia to the site. And if you can't visit, you can subscribe to free newsletters to get the latest arts news and comment by email.

Our Website of the Week is, or get the link from our site,

MUSIC: Hal McKusick — "For Art's Sake"

You're listening to VOA's science and technology magazine, Our World. ArtsJournal? Hey, what did you expect from your host, Art Chimes in Washington.

Competitions of various sorts have been in the news recently. A couple of weeks ago the X Prize Foundation announced a $25 million prize for the first privately-funded robotic rover sent to the moon. And then there was another, more down-to-earth competition that doesn't offer as much money, but on the other hand you don't have to be a rocket scientist to enter.

LaPOINTE: "Ruckus Nation is a competition to find ideas to get young people, age 11-14, to be more physically active. In Ruckus Nation, anyone can enter their ideas and win. They can win the opportunity to help kids. They can win recognition for their idea. And they can win cash prizes."

Cash prizes up to $75,000, in fact, says Ellen LaPointe of HopeLab, a non-profit organization that focuses on disease and young people. Their latest project, called Ruckus Nation, is targeting what many experts consider an epidemic of childhood obesity in the United States.

Government surveys indicate that more than one American child in six is overweight, and that number has climbed steadily in recent years. Better nutrition is part of the solution, but so is finding ways to get kids away from TV, the Internet and video games, to become more physically active

VIDEO: "What will be the next big thing that gets kids moving?"

ONYEKERE: "Because there's no better source from which to draw cool, creative products that get kids moving than from kids themselves and other consumers that this competition will reach."

Chinwe Onyekere is with the Robert Wood Johnson Foundation, which is co-sponsoring the competition. She adds that, without the tools to help combat childhood obesity, today's young generation will live sicker and perhaps die younger than their parents.

Although the Ruckus Nation contest is targeted at American kids, it's open to residents of almost all countries, and who knows where the best idea will come from. You can find out more at, or we'll have a link on our site,

Parasites cause a wide range of health problems for humans and wildlife. Over the past decade, scientists have been tracking an alarming increase in frog deformities. One identified cause is a parasitic infection. But what caused the surge in parasites? Véronique LaCapra reports on a new study that looks at the role of nutrient pollution.

LaCAPRA: Nutrient pollution of lakes and ponds comes from a variety of sources, including agricultural fertilizers and sewage. Known as eutrophication, it can cause substantial changes to freshwater systems.

Until now, little research had been done into how eutrophication might affect waterborne parasites, which cause health problems ranging from skin rashes to river blindness.

Ecologist Pieter Johnson of the University of Colorado set out to test the effect of nutrients on one particular parasite, a flatworm that infects frogs.

JOHNSON: "We were interested in how eutrophication can influence patterns of infectious disease generally, and then, what factors might be controlling the abundance of parasites that cause deformities in frogs."

LaCAPRA: Frog deformities first gained widespread attention in 1995, when a group of school children in the midwestern United States came across a pond where more than half of the frogs were abnormal.

JOHNSON: "Since then reports have really poured in from all over the place, and there's been a lot of debate and controversy over what's causing this."

LaCAPRA: Research has shown that ultraviolet radiation, exposure to pesticides and other chemicals, and parasitic infections all can cause deformities in amphibians. In the case of the parasite, the target is the base of the tadpole's tail, where the hind legs develop. Infected tadpoles grow into frogs with too many legs, abnormal legs, or sometimes no legs at all.

JOHNSON: "The animals with these deformities don't jump very well, they don't swim very well, and they're essentially fairly debilitated."

LaCAPRA: Johnson says the deformed frogs make an easy target for birds and other predators, and generally do not survive.

JOHNSON: "As a result, there's concern that deformities are contributing to large-scale patterns of decline in amphibians worldwide."

LaCAPRA: The frogs are just one of three hosts that this deformity-causing parasite infects as part of its complex life cycle. The parasites also infect freshwater snails, and birds. The parasites multiply inside the snails, then emerge to infect the frogs, some of which are eaten by birds.

In an effort to better understand how eutrophication might affect the parasite's life cycle, Johnson and his colleagues added nutrients to a set of small artificial ponds. Some ponds got more nutrients, and others less.

JOHNSON: "Our goal then was to watch how adding nutrients cascaded through the lifecycle of this parasite, to ultimately affect the levels of parasitism in the frogs."

LaCAPRA: The nutrients acted as fertilizer for the algae, which meant more food for the snails. More snails, in turn, meant more hosts for the parasite.

JOHNSON: "Under higher nutrient conditions there were a lot more parasites, anywhere from 2 to 5 times more parasites, that were getting into the amphibians."

LaCAPRA: Johnson says the next step is to try to understand how the parasites are affecting frog populations:

JOHNSON: "We know that deformed animals do not survive to maturity, and we know that parasites can often kill large numbers of frogs, but what the long-term consequences of that are for amphibian population viability and amphibian population declines still remains largely unexplored."

LaCAPRA: His results could have implications for other parasitic infections, as well:

JOHNSON: "Eutrophication could be affecting other diseases that we care about, including both diseases of humans and those of wildlife, that really warrant closer examination."

LaCAPRA: More information about this study is available in the September 24, online edition of the Proceedings of the National Academy of Sciences. I'm Véronique LaCapra.

On Thursday the US space agency NASA sent its latest unmanned probe off on a 2.7 billion kilometer journey of discovery.

DAWN LAUNCH ANNOUNCEMENT: "... Two. Main engine start. One. Zero and liftoff of the Delta II rocket with Dawn, using ion propulsion to reach the catalysts of our solar system. ..."

The Dawn spacecraft is on its way to the asteroid belt between Mars and Jupiter, where it will visit the region's largest objects, Vesta and Ceres.

NASA official Jim Adams described the mission's science goals at a post-launch press conference.

ADAMS: "We're hopeful that in four years time we'll begin to understand better the history and the evolution of our solar system as a result of the observations that Dawn will bring to us."

Dawn won't arrive at its first destination until 2011. It's taking that long because of the distance and because once in space, Dawn is powered by an ion engine, which uses less fuel than chemical rockets, but also travels at slower speeds. Dawn's science instruments will measure the two asteroids and study their chemical composition, as well as seek out water-bearing minerals.

Dawn was launched just one week shy of the 50th anniversary of the launch of Sputnik 1. On October 4, 1957, a Soviet rocket blasted into space, carrying the world's first artificial satellite. Sputnik's radio transmitter announced the beginning of the Space Age.

The space race was on.

In 1961 Moscow scored yet again: the first man in orbit. The Americans played catch-up, with a quick, sub-orbital flight, but then the U.S. pulled ahead, landing a man on the Moon, just 12 short years after Sputnik. Three years later it was over, and humans haven't been back to the Moon since 1972. The next visitor, in fact, may be neither American nor Russian. How do you say "one small step" in Mandarin?

By now, we were supposed to have colonies on Mars, vacation resorts on the Moon, and spaceplanes delivering passengers halfway around the world in a couple of hours.

But, as American baseball player Yogi Berra supposedly said, "the future ain't what it used to be."

What we got instead were robotic spacecraft that have completely revised our knowledge of the Solar System. And vastly improved weather forecasts. And Global Positioning System devices that help hikers and motorists find their way home. And technologies that have made their way into countless products from home to hospital. And communications satellites that bring live news events, a world of entertainment, and even this program into your home.

That's some of what we got in the first 50 years of the Space Age. Makes you kind of wonder what the next 50 years will be like.

MUSIC: "Our World" theme

That's our show for this week. We're always interested in your comments or your science questions. Email us at Or use the postal address —

Our World
Voice of America
Washington, DC 20237 USA

Rob Sivak edited the program. Eva Nenicka is the technical director. And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.