Space Shuttle Flights Halted / Researchers Study Icelanders' Genes / Another Reason to Eat Green, Leafy Vegetables
This is Steve Ember. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell why researchers are studying the genes of people in Iceland. We tell why American space officials have suspended the launch of the space shuttles. And we tell why you should eat green, leafy vegetables.
Genes are the parts of cells that control the growth and development of living things, including people. Now, a company in Iceland is working to create the most detailed map yet of all known human genes. The company, Decode (Dee-code) Genetics, is based in Reykjavik, Iceland. Kari Stefansson (COW-ree STEF-ahn-son) is head of the company.
Doctor Stefansson believes that the people of Iceland present a special chance to study the human genome and how some genes cause disease. Iceland has a very small population – about two-hundred-eighty-thousand people. The majority of the population shares a small group of common ancestors who lived thousands of years ago. The people of Iceland keep extensive records of their ancestors. In addition, Iceland has an excellent health care system. Doctor Stefansson says his researchers are studying genetic diseases in many families over hundreds of years.
Decode paid Iceland about two-hundred-million dollars to do the study. So far, researchers have examined the genes of at least one-hundred-forty-six families. The Iceland genome project is using a much larger group of individuals to observe differences in human genes than any other project. For example, American scientists made a genetic map based on only eight large families in France.
Decode plans to examine genetic information from a huge number of Icelanders. The New York Times newspaper reports that Decode has collected blood from about sixty-five-thousand Icelanders. That is about one-third the adult population of Iceland.
Huntington Willard is a genetic scientist at Case Western Reserve University in Cleveland, Ohio. He says that the information provided by the Iceland genome project will help complete a map of the human genome. He says that the genome published in Science magazine in February of last year by a group of researchers was not complete and contained many mistakes.
Two years ago, scientist J. Craig Venter made the surprising announcement that his company, Celera Genomics, (suh-LAIR-uh Jeh-NO-mix) had mapped the whole human genome. Mr. Venter is no longer the head of Celera. The company had hoped to gain legal rights to some parts of the human genome and to sell the use of that information.
However, Doctor Willard says the new information shows how to correct problems with the current human genome map. The Decode map's success is partly based on its larger base of information.
Human beings have almost exactly the same genes. Small genetic differences make us look different from each other. These differences can also make us more likely to get some diseases.
Decode's main project is to identify genes that cause disease. Scientists believe most common diseases are caused by several abnormal genes working together. The Icelandic company says it has mapped the general area of genes for twenty common diseases. These include Alzheimer's disease, Parkinson's disease and rheumatoid arthritis. The company claims to have found three disease-causing genes already. They are linked to a mental disease and two kinds of strokes.
Decode uses a process that can identify very small molecular differences. This permits scientists to find disease-causing genes more easily. Decode's more detailed method for studying genes also permits it to create a clearer map of genes. This is why Decode has shown errors in earlier genome maps.
Experts say the Icelandic study appears to be important for creating a truly useful genetic map. The United States government's National Institutes of Health is also working on a map of the human genome. The N-I-H says that a new, corrected map should be finished next year. It says the announcement should be in time for the fiftieth anniversary of the discovery of the structure of human D-N-A. D-N-A is the nucleic acid found in genes.
Two scientists, James Watson and Francis Crick, were the first to describe the structure of D-N-A in nineteen-fifty-three. They were awarded the Nobel Prize for Medicine along with Maurice Wilkins in nineteen-sixty-two. The three scientists discovered the structure of D-N-A. However, fifty years later, geneticists are still trying to learn what that structure means.
American space agency officials have temporarily suspended launch plans for the Space Shuttle Columbia. Columbia was to have been launched July nineteenth.
NASA officials decided to delay the launch after several damaged areas were found in the fuel lines on the main engines of the shuttles Atlantis and Discovery. These are two of the four vehicles that take astronauts into space and to the International Space Station.
James Hartsfield is a spokesman for the Johnson Space Center in Houston, Texas. He said NASA's main concern is the possibility that a piece of metal in the fuel line would separate and move into the space shuttle's engine area. This would damage the engine and cause it to shut down.
Mr. Hartsfield said NASA workers have never seen the damage before. He said the parts of the space shuttles that are now damaged have been on the vehicles since they were built. He said the workers do not know if the damage was caused by age or if other problems are involved. He said they consider the problem to be a major safety concern.
Ron Dittemore is the Space Shuttle program manager. He says that NASA has more questions than answers about the damage. He says NASA workers are investigating the situation. Workers will inspect the Space Shuttle Columbia for similar damage. Columbia is the oldest of the four space shuttles. It is twenty-one years old.
NASA says it takes a week or more to remove a space shuttle's engines and the same amount of time to replace them. Officials say they do not yet know how long all United States shuttle flights will be suspended.
Recent research has suggested that a nutrient called lutein (LOO-teen) may improve health in more ways than had been thought. Lutein is found in green, leafy vegetables like spinach and lettuce. It is also found in other fruits and vegetables such as oranges, corn and broccoli. And it is found in the yellow part of eggs.
Lutein is also found in the human eye. Lutein and similar substances known as carotenoids (ca-ROT-en-oids) make up the color in the macula, the area of the eye responsible for seeing fine detail. Studies have suggested that greater amounts of carotenoids increase the color of the macula. Scientists believe that more color protects the macula from damage.
A study in the publication Optometry says that eating more foods with lutein may improve vision in people with eye problems. Another study linked greater levels of carotenoids with reduced early signs of macular damage. And two large studies have linked lutein to fewer problems with the eye condition called cataracts.
Now, research has begun to show that lutein can protect health in other ways. A report in the publication Circulation says it may reduce the chance of heart attacks and strokes. People with higher blood levels of lutein had less of a harmful substance inside their blood vessels.Other studies have suggested that lutein may protect against cancers of the breast and colon.
Researchers in Boston, Massachusetts have shown that lutein in dark green, leafy vegetables can protect the skin against damage from the sun. They experimented with mice that were fed foods containing lutein. Experts say people should eat foods that contain lutein every day.
This SCIENCE IN THE NEWS program was written by Mario Ritter, Paul Thompson and Nancy Steinbach. It was produced by Nancy Steinbach. This is Bob Doughty. And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.