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Our World — 8 September 2007

MUSIC: "Our World" theme

Straight ahead on "Our World" ... new data describe a more genetically diverse human species ... a clue to the mystery of the disappearing honeybees ... and why oceans are salty.

NEMERSON: "And what happens is, in the ocean basically the water gets distilled. Sunlight falls on the surface of the ocean, evaporates off that fresh water and leaves the salts behind in the ocean."

Those stories, the challenge of preserving endangered livestock breeds and why it's important to save them, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

New research published this week indicates the genetic variation within the human species is greater than previously thought.

When the human genetic code was first deciphered in 2001, it appeared that all humans were 99.9 percent alike — in other words, only one-tenth of one percent of human DNA differs from person to person. Now, says genetic researcher Craig Venter, that human-to-human variation could be ten times greater —

VENTER: "Substantially more different from each other. We've been speculating that it could be as high as one to two percent in the population."

Craig Venter is the scientist whose then-company, Celera Genomics, challenged a government consortium to be the first to sequence the human genetic structure. The result from both the public and private efforts was really a composite - one stretch of genetic code from this man, another stretch from that woman.

Venter's conclusion about dramatically more human genetic diversity comes from a third human genetic sequence — his own, which was unveiled this week. And unlike the previous composite gene sequences, his includes both strands of the DNA's famous double helix, which were analyzed separately. One comes from the father, the other from the mother.

The result of studying this so-called diploid genome, Venter told reporters, was that the extent of genetic diversity became more apparent. He was able not only to compare his own DNA to the two previous composites, but also to see more clearly the differences between the genetic bits he inherited from his mother and those from his father.

VENTER: "There's one gene associated with metabolizing environmental toxins. One of my parents had no copies of that gene and one had one. So one of the chromosomes I have is blank at that spot, and the other has that gene.

The scientist, who heads his own non-profit research organization, the J. Craig Venter Institute, believes the diversity evidenced in his own genome is a welcome discovery.

VENTER: "I think this is actually good news for humanity, that we are slightly more variant. It looked like we might all be clones back in 2001. We've clearly moved beyond that."

Many scientists believe that the ability to know a particular individual's genetic code could allow customized medicines to be tailored to individual patients. That's still in the future. And anyway, the cost of sequencing Craig Venter's genome was estimated in the tens of millions of dollars. But the researcher believes that as the process becomes more automated, it will become cheaper, and in the coming years it could become a fairly routine process.

VENTER: "We expect over the next three to five years to maybe have at least 10,000 diploid human genomes. Ten million would be better. And once we have those we will be able to sort out basically every fundamental question about nature versus nurture — what's genetic, what's environment — what are all the minor variations that show up in all of our genomes that actually contribute to our individual traits, risk for disease, etc. I think this will have an impact on preventative medicine [and] I think just a deeper understanding of us as a species and our own evolution."

A report on the sequencing of Craig Venter's genome was published this week in the journal PLoS Biology. Samuel Levy, the lead author, explained that although this is the most complete genome ever decoded, there are still some small missing pieces, which he expects will be filled-in as the technology improves.

LEVY: "There are gaps still present. However those gaps are easily closed with the increased coverage that we are currently putting together using, as Craig mentioned, some of the newest sequencing technologies. Once we improve the coverage rate to two- to three-fold more than where we are currently, we suspect this will be a complete genome. So I think we're very close to having this complete."

For many people, the idea of learning all the secrets embedded in their DNA is, well, scary. But if you know your genes increase your likelihood of disease you might want to stop smoking, say, or improve your diet or get more exercise. Craig Venter believes the information will empower us:

VENTER: "We hope to help teach people they should welcome this information as a breath of fresh air that gives them opportunities in their lives to perhaps change things."

I've got a big poster over my desk that's sort of a generic map of the human genome. Craig Venter, I guess, is the only one right now with his own personalized version. Someday, maybe a lot of us could.

Genetic technology also made this next story possible: the identification of a virus that may be responsible for colony collapse disorder. That's the name used to describe the mysterious disappearance of honeybees from hives in North America and Europe. It's an especially worrisome problem for farmers, who depend on honeybees to pollinate many important crops. But anything that affects the food supply obviously concerns anyone who eats.

The 22 co-authors of a paper published online this week in Science Express are careful not to say the virus, known as IAPV, is the cause of colony collapse disorder, or CCD. They don't have enough evidence for that, yet. But there is a relationship between the two, and lead author Diana Cox-Foster says it's a promising clue.

COX-FOSTER: "In this study we've had opportunity to find a relatively new virus to the United States, or a brand new virus to the United States. It appears to be associated with colony collapse disorder. Whether it's a causative agent or a very good marker is the next major question that we need to address."

Colony collapse disorder has affected more than half the commercial honeybee hives in the United States. The importance of bees as agricultural pollinators has made identifying the source of CCD a top priority for researchers.

In their attempt to identify the cause of the problem, the scientists used genetic sequencing techniques to identify all the microorganisms in the bees. That led to new discoveries about the bee's internal micro-ecosystem.

Edward Holmes of Pennsylvania State University says they discovered a number of viruses, in addition to the one that appears to be linked to CCD.

HOLMES: "So we're really left with this remarkable situation now where we know these bees carry this remarkable diversity of viruses. We think one is strongly associated with CCD. But the bigger question is really how these viruses interact in the population. That we really don't know."

In addition to the viruses, Researcher Nancy Moran of the University of Arizona says they found previously unknown bacteria, mainly in the guts, the intestines of bees. They don't appear to have anything to do with CCD, however, since they were found in both sick and healthy bees. And Moran says the role these bacteria play is unclear.

MORAN: "In other insects it's known that bacteria can provide essential nutrients that the insect requires for nutrition, or that they can contribute defenses against pathogens or natural enemies. At this point we don't know what these bacteria are doing in bees, but we know they're present in all bees sampled and they're a very distinctive set."

The suspect virus was first identified by a researcher in Israel, so it's called Israeli Acute Paralysis Virus — IAPV for short. And if IAPV is the cause of colony collapse disorder, or even if it just contributes to it, the research here reported this week could provide a blueprint to help combat the puzzling phenomenon. Jeff Pettis of the U.S. Department of Agriculture says nailing down the cause will be a next step.

PETTIS: "I still believe that multiple factors are involved in CCD and we must test those combinations in a more rigorous fashion. As scientists, it's very easy for us to manipulate a single variable, but what we really need to do is begin to look at combinations of things, such as the interactions between varroa [parasitic mites], pesticide stress, and nutrition."

Pettis adds that identifying those other contributing factors may be even more important to solving the problem. In the meantime, those who keep bees should do what they can to keep their hives as healthy as possible by following good beekeeping practices.

PETTIS: "Let's say this virus story was true and it was working in combination with some other factor, we're not going to likely come up with a treatment for viruses in bees. So we're going to have to manage the other part, the parts that we can manage, and keep the virus levels at low levels so that they're not affecting bee health."

Jeff Pettis stresses that the problem of colony collapse disorder has not yet been solved, and that much more research is needed to completely understand this puzzling and potentially devastating problem.

Incidentally, while the researchers are not completely ruling out other possible causes of colony collapse disorder, they say it appears increasingly unlikely that it's due to electromagnetic radiation from mobile phones or the impact of genetically modified crops. Chemical pesticides, however, are still being studied as a possible contributing cause.

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

This week, an online, interactive museum on the history of electrical technologies.

Michael Geselowitz says that for more than 100 years, engineers and scientists have been developing more and more clever technologies to use electricity.

GESELOWITZ: "And the IEEE Virtual Museum is a website where the public can go to explore the histories of these technologies, learn something about the people who invented them, learn about their impact on society, and so forth."

The IEEE Virtual Museum is presented by the Institute of Electrical and Electronics Engineers, including more than 370,000 specialists in electronics, computers and related fields in over 160 countries. Their online, virtual museum starts out with an introduction to electricity called "Socket To Me" — a history lesson that begins with the ancient Greeks.

GESELOWITZ: "And that exhibit, which is our most popular exhibit, is a general outline of the whole history of electrical science and engineering. Then we have, over time, we've built additional exhibits focusing on specific aspects. So for example, the next most popular exhibit is our one on microwaves."

Some other exhibits in the IEEE Virtual Museum focus on nanotechnology, on electronics and women, and on sound recording, to name just a few. And if you want to go into greater depth, the director of the IEEE History Center, Michael Geselowitz, says each exhibit has a collection of clickable links that allow you to dig deeper into the subject.

GESELOWITZ: "As you follow the story in the exhibit, you go from page to page in an exhibit, you see on the side of the page ways you can find more about something that's mentioned in the exhibit. So if the exhibit mentions Thomas Edison, you'll see a Thomas Edison link on the right, and if you click there you get a page with a picture of Thomas Edison and a brief biography."

Learn more about electricity and the electronic devices that enrich our lives at the IEEE Virtual Museum i e e e hyphen virtual hyphen museum dot org or get the link from our site,

MUSIC: Van Dyke Parks — music from a 1969 television commercial

It's VOA's science and technology magazine, Our World. I'm Art Chimes in Washington. It's electric!

Whether they are the result of a house fire, a cooking accident, or a highway crash — burns are among the worst kinds of injuries. Many are fatal, and burn survivors — even those who get the very best care — have a tough road back. As we hear from health reporter Rose Hoban, some researchers in California are working on new techniques to improve the outcome for burn patients.

HOBAN: People who are burned have a long, painful recovery and when their skin grows back, many are left with permanent, disfiguring scars. These so-called hypertrophic scars occur when skin cells grow too much during the healing process. When hypertrophic scars form over joints like the elbow — where skin is continuously stressed — the taut, inflexible scar tissue can severely reduce mobility and cause constant pain.

There's been little progress in reducing the hypertrophic scarring associated with burns, according to plastic surgeon Jeffrey Gurtner from Stanford University Hospital in California. He and a team of researchers have been looking at the healing process after burning. Gurtner says it's an unsolved problem in medicine — they really don't know why these disfiguring scars form.

GURTNER: "And the reasons have been that there's no good animal model to study the causality of certain effects, and so most of the understanding that we have is based on clinical observation."

HOBAN: Gurtner and his colleagues did eventually find an animal model to compare to human skin - the mouse. Gurtner says mouse scar tissue does not hypertrophy and grow out of control the way human tissue does.

GURTNER: "And what we did in the mouse was actually increase the amount of mechanical stress so that it healed exactly like a human hypertrophic scar would."

HOBAN: Gurtner says they learned a lot from the stress — the pulling and bandaging — applied to the mouse skin as it healed. They went on to experiment with pig skin, as pigs do form hypertrophic scars the way people do. Gurtner and his colleagues found that if they put an apparatus on the burn that reduced the amount of pulling on the skin as it healed, the scar tissue that formed was not as thick.

GURTNER: "I guess, the fact that people hadn't tried this approach before was somewhat surprising because it's been known for literally hundreds of years that you can predict in certain places how scars will heal based on the amount of mechanical forces that are acting on them."

HOBAN: Gurtner says their preliminary studies on pig skin are encouraging and he expects that within a year or two, they'll be able to try these techniques on people who are healing after a burn. His first study appears in the online journal Public Library of Science: Medicine this month. Gurtner says they'll have additional research published this fall in the journal of the Federation of the American Society of Experimental Biology. I'm Rose Hoban.

Time again to dip into the Our World mailbag to answer a science question from a listener. This time, we have a letter from Ejie Okechukwakadibia at the University of Port Harcourt, in Nigeria, who wants to know what makes the ocean salty when the water flowing into the ocean — such as from rivers — is not.

You know, this is one of those great questions — like, why is the sky blue — that is so easy to take for granted.

For the answer, we consulted David Nemerson, a biologist at the terrific National Aquarium in Baltimore.

NEMERSON: "The listener is certainly right, that the water that flows into the ocean from rivers and streams doesn't seem salty, but it actually is a little bit salty. Even rainwater that seems perfectly fresh has a very small amount of dissolved salts in it. And basically what happens is the water that flows down through the rivers and streams into the ocean brings large quantities of salts to the oceans simply because there are so many rivers flowing down into the oceans. And what happens is, in the ocean basically the water gets distilled. Sunlight falls on the surface of the ocean, evaporates off that fresh water that goes up into the clouds and becomes more rain and leaves the salts behind in the ocean. And over time that is just simply concentrated in the amount of salt that's in the ocean.

Nemerson says that until recently, virtually all of the salt in the ocean was thought to have originated on land. Now, though, it's understood that the geology of the oceans themselves also contributes to the process.

NEMERSON: "A fair amount of the salts that wind up in the oceans actually come things like deep-sea hydrothermal vents and deep-sea volcanoes, and other sources underneath the ocean that release salts into the ocean."

Notice he talks about salts, plural. The main one is sodium chloride, the white crystals we put on our food.

NEMERSON: "But there are many, many other dissolved salts and a myriad of other chemicals that are dissolved in seawater. It's a complex stew.

David Nemerson of the National Aquarium in Baltimore adds that the ocean is not uniformly salty. There's more salt in the oceans in hot and dry areas where there is less rainfall and more evaporation. On the other hand, there's less salt in polar regions, where ice is melting, snow is falling, and there's not much evaporation because it's cold.

Thanks again to Ejie Okechukwakadibia for sending in a great question. We'll be sending a little VOA gift as our way of saying thanks. If you've got a science question, please send it to us. If we use it on the air we'll send you a gift, too. Our email address is, or listen for our postal address at the end of the show.

A new report from the United Nations says a growing number of farm animals worldwide are in danger of extinction. The report by the United Nations Food and Agriculture Organization, or FAO, was released this week at an international conference in Switzerland. VOA's Rosanne Skirble reports.

SKIRBLE: The FAO's global analysis of farm animals worldwide finds that of the 3,000 breeds reported between 1999 and 2006, 45 percent are either at risk or already extinct. The loss is rapid. About one breed a month disappears from the planet, forever.

The threat is especially acute in developing countries, which are home to 70 percent of the world's remaining livestock breeds, and which are least able to afford to protect them.

Ed Rege with the International Livestock Research Institute contributed to the FAO report. He blames the problem on the world's over-reliance on a handful of farm animal species.

REGE: "The demand for high quality protein sources, particularly livestock source foods is increasing at such high rates that countries are opting for short and quick measures such as replacing their breeds with high producing but obviously less adapted breeds from the north."

SKIRBLE: Take the case of Ethiopia, where since the 1960s the native Sheko has been replaced with the black and white Holstein-Friesian dairy cow, which although, a high milk producer, is large in size and consumes a lot of feed.

REGE "So bigger animals are coming in and this animal is being replaced rapidly by direct replacement as well as cross breeding. In the process we are loosing what we know which is the tolerance for trypanosomosis. We are also losing what we don't know, which is that this animal is considered to be resistant to other diseases. [Those diseases] have not been sufficiently characterized."

SKIRBLE: Rege says the critical importance of preserving native livestock breeds was demonstrated not long ago in war-torn Mozambique, where native cattle were wiped out as a result of civil turmoil:

REGE: "Donors were seeking ways to actually restock cattle in that country and what they could use basically had to be something that fitted in the environment. And, they used whatever data was available to go to neighboring countries and find similar breeds. Not necessarily identical, but close enough to be able to give farmers low-risk breeds that they could introduce in their villages."

SKIRBLE: Rege says this strategy can help guard against loss from changes in the market, or from disease, natural disaster or war. That's why the FAO report recommends that farmers be given financial incentives to keep raising and selling their native breeds. The report also urges more research to determine which breeds will adapt best to climate change, and calls for the expansion of animal gene banks for those livestock species at greatest risk.

REGE: "That can then be used as security should there be a particular breed that is lost or that is threatened that needs to be reinvigorated genetically."

SKIRBLE: Rege hopes the FAO report helps raise awareness among policy makers and farmers alike.

REGE: "If farmers are made aware and have the information that they can use to critique some of the decisions being made by governments or some of the lack of action that the government may be accused of at this time."

SKIRBLE: In other words, that local farmers can play an important role [for change].

REGE: "Precisely! Farmer awareness and feedback from farmers will be critical. So if farmers are pushing for these things then the politicians will realize that yes, 'My constituency [is] asking me to legislate in this way.' That will then translate into longer term set of actions put in place."

SKIRBLE: Rege says maintaining breed diversity will also help millions of people work their way out of poverty. Seventy percent of the world's rural poor depend on livestock for both food and income. I'm Rosanne Skirble.

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.