I’m Bob Doughty with Sarah Long, and this is the VOA Special English program, SCIENCE IN THE NEWS.
This week -- the horse family enters the world of cloning. Finding a system to help countries share their observations of Earth. And, scientists say human activity is raising a part of the atmosphere you may not even know we had.
Sheep, pigs and other animals have all been copied through genetic engineering in recent years. Now scientists in Italy have cloned a horse for the first time. Not only that, this horse is an exact copy of the animal that gave birth to it. Clones such as Dolly the sheep were created with DNA from animals other than their birth mothers.
Nature magazine published the details this month. The cloned horse arrived May twenty-eighth in the Laboratory of Reproductive Technology in Cremona, Italy. Researcher Cesare Galli (KAYS-ah ray-GAH-lee) led the team.
|The first cloned horse, Prometea.|
The scientists in Italy said that after two months Prometea was healthy and weighed more than one-hundred kilograms.
Scientists were not sure what would happen if they tried to have a mother, in effect, give birth to herself. They thought a mother’s body had to recognize a fetus as different. They believed a pregnancy would fail if this did not happen.
Prometea arrived as living proof that a horse, at least, can be born from its mother and at the same time be a genetic copy of its mother. The experiment means that scientists might be able to copy valuable race and show horses.
But the process that led to Prometea was difficult. To create her, the team had to work with more than eight-hundred rebuilt embryos.
The researchers took skin cells from a female Haflinger horse. They also took skin cells from a male Arabian horse. Then they removed the nucleus from each cell. The nucleus contains the DNA material, the complete genetic plans for an organism.
Next, the researchers took a nucleus from either the female horse or the male horse and put it into an egg. They had collected the eggs from horses killed at a slaughterhouse and taken out the existing nucleus.
With help in the laboratory, twenty-two of the eggs developed into embryos. The scientists then placed these embryos into female horses.
Out of four pregnancies, only Prometea was born. She happened to be born to the same horse whose DNA was used in the embryo.
It is too soon to know how cloning might affect the horse racing and breeding industries. Several officials who welcome the process point to the example of Funny Cide.
This horse won two top races in the United States this year, the Kentucky Derby and the Preakness. But Funny Cide was neutered early in life to prevent him from reproducing. Cloning could give birth to copies of Funny Cide with his own DNA.
Entering cloned horses into events, however, could be difficult. The international racing industry for top horses has rules against clones.
Science could also use cloning to help save populations of endangered horses. These would include the Przewalski’s [sheh-VAL-skeez's] horse of Mongolia.
Horses are members of the equine family. Until now, scientists have not had much luck with attempts at artificial reproduction of equines. A team at Texas A&M University in the United States was in a race with the Italians to clone the first horse.
But the scientists in Italy cannot claim Prometea as the first cloned equine. Two weeks earlier, a mule named Idaho Gem arrived in the American Northwest. A mule is a mixture of a horse and a donkey.
It all happened at the University of Idaho, in Moscow [MOSS-co], Idaho. Scientists led by Gordon Woods took DNA from a mule fetus and placed it into the egg of a female horse. Unlike the Italian team, they used eggs from live horses.
The scientists used chemicals to cause the eggs to begin the normal process of dividing into embryos. Then they placed the embryos into female horses. They experimented with more than three-hundred embryos. From these, Idaho Gem was born. Then two more cloned mules arrived later.
Most mules cannot reproduce. So cloning may offer another way to carry on their genes.
From VOA Special English in Washington, this is Science in the News.
|Ocean Explorer Satellite.|
The committee was chosen in Washington during the recent Earth Observation Summit. Government ministers attended from more than thirty nations and the European Commission. Representatives of non-governmental organizations also attended the conference.
The committee is to develop a plan by the end of two-thousand-four. The goal is to let nations and groups exchange information collected about areas like water and climate conditions.
|A image of earth's ozone.|
Many countries collect information about the environment. This information comes from different systems. These include devices in the ocean as well as satellites in space. American satellites, for example, record information such as sea levels and changes in the amount of Arctic ice.
Conrad Lautenbacher is director of the National Oceanic and Atmospheric Administration. He will serve on the committee that will form the plan. He is a retired vice admiral in the United States Navy. Admiral Lautenbacher says scientists have been interested in a shared observation system for many years.
Officials say the new system could lead to such things as better crops. They say it could also save lives, by helping nations to keep better watch on the environment they share.
A study finds that human activities are a leading cause of an increase in the height of the tropopause. That is what separates the two lowest levels in our atmosphere. The troposause is between the troposphere and the stratosphere. Because of its position, scientists believe it can offer clues about warming in the lower atmosphere.
The tropopause is about eight to sixteen kilometers above the surface of Earth. Studies show it has risen by a few hundred meters since nineteen-seventy-nine. Scientists say this increase does not directly affect Earth. But they say it shows that temperatures are rising in the troposphere below, while the stratosphere above is getting cooler.
Under natural conditions, temperatures get warmer with height in the stratosphere, and cooler in the troposphere.
Science magazine published the study. Benjamin Santer of Lawrence Livermore National Laboratory in the United States led the team. Scientists from the National Center for Atmospheric Research also took part.
The study examined five possible reasons for the increased height of the tropopause.
One was radiation from the sun. Another was volcanic activity. A third was the release of industrial gases that trap heat, such as carbon dioxide. The fourth was the release of sulfur dioxide gas. Finally they examined levels of ozone, a natural form of oxygen in the atmosphere.
Computer experiments showed that ozone loss combined with industrial pollution caused more than eighty percent of the rise in the tropopause.
The study says industrial gases have warmed the troposphere, while ozone loss has cooled the stratosphere. Scientists blame the loss of ozone largely on ozone-destroying chemicals.
The researchers say the study provides more evidence that pollution is having an effect on the atmosphere and climate change.
Earlier this year, Science magazine published findings about temperatures in the lowest reaches of the atmosphere. Scientists reported an increase of about two-tenths of one degree Celsius between nineteen-seventy-nine and nineteen-ninety-nine.
SCIENCE IN THE NEWS was written by Jerilyn Watson and George Grow. Our producer was Mario Ritter. This is Sarah Long.
And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.