SCIENCE IN THE NEWS - New Genetic Map Called a Powerful Tool（在线收听）

SCIENCE IN THE NEWS - New Genetic Map Called a Powerful Tool for Medical Science
By Jerilyn Watson and Caty Weaver

Broadcast: Tuesday, November 15, 2005

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This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty.

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And I'm Pat Bodnar. This week -- news about a genetic map that is being called a powerful new tool for medical research ...

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Then, a report on an ancient Christian church found under an Israeli prison ...

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And Angola says a recent outbreak of Marburg virus is over.

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Small genetic differences make one person different from another. Now medical researchers have a new map to help them find these differences. More than two hundred scientists from six nations developed the HapMap. The name comes from the word haplotype.

 
 
A haplotype is a group of differences that are likely to collect close together, in a block. These blocks appear to pass from parent to child. The HapMap scientists hope to identify up to six million DNA differences before they finish.

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The scientists say the findings may lead to identifying genes that cause common diseases like diabetes and heart disease. Linking diseases to genes could lead to new treatments. People could also learn if they have an increased risk of a disease because of their genes.

In some cases, such knowledge might lead to preventive action. For example, people whose genes show a possibility of developing diabetes could take steps like trying to control their weight. But for a condition like Alzheimer's disease, nothing known today could prevent it.

The scientists have published their work in Nature magazine and on the Internet at hapmap dot o-r-g (hapmap.org).

An organization called the International HapMap Consortium organized the study. The work involves researchers from Britain, Canada, China, Japan, Nigeria and the United States.

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The new map is based on DNA from two hundred sixty-nine people. They represent four ethnic groups: European, Japanese, Chinese and Yoruba.

Project leader David Altshuler works at Massachusetts General Hospital and Harvard Medical School. He also directs medical and population genetics at the Broad Institute in Massachusetts. Another project director, Peter Donnelly, is from Oxford University in England.

Doctor Altshuler calls the HapMap a powerful new tool to explore the root causes of common diseases. It is more difficult for scientists to find genes linked to common diseases than to rare ones.

For example, one single gene may be responsible for a rare genetic disease within the same family over the years. But several genes may cause a person to be more likely than others to get some kinds of cancer.

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The HapMap Project developed from information provided by the Human Genome Project. That project was completed in two thousand three. It identified all the chemical pieces in DNA, the genetic material in cells.

DNA has more than three thousand million building blocks. A series of these building blocks forms a gene. For any two people, the building blocks are almost all the same. But extremely small differences can mean that one person has a higher risk of disease.

One kind of difference is called a SNP [pronounced snip]. There are millions of places where SNPs can happen. The HapMap Project is identifying common places where they are found.

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Studying haplotype blocks will make it easier to find the genes suspected of causing a disease. The researchers may be able to investigate which blocks of DNA are common among people with the same disease. The process would be much faster than examining every piece of DNA.

Stacey Gabriel of the Broad Institute says mapping just one SNP used to cost almost a dollar per patient. Today, she says, it often costs less than one cent. In the past, it was possible to test only one hundred genotypes in a day. But now, she says, it is possible to perform millions of tests in a day.

In the past, some scientists have questioned whether using haplotypes is the best way to find genetic information. Some still express concerns about the effectiveness of this method. But several studies already have been published using the new information.

For example, scientists at Yale University in New Haven, Connecticut, used the HapMap to connect a gene to macular degeneration. That is a leading cause of blindness in older people.

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You are listening to SCIENCE IN THE NEWS in VOA Special English, from Washington.

Palestinians in a prison in Israel have found the ruins of an ancient Christian place of worship. Some archaeologists say it could be the oldest church ever found in the homeland of Jesus. But other experts say it is unlikely the church is as old as suggested.

 
Israeli prisoners Ramil Razilo, top, and Meimon Biton clean a part of a Christian mosaic floor at the Megiddo prison in northern Israel
The prison is in Megiddo. Israeli officials had ordered a dig to search for ancient objects before a planned addition to the prison. The government often orders such digs before building in historically important areas. Megiddo is where the battle of Armageddon takes place in the Bible.

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The Israeli Antiquities Authority began the dig months ago with about sixty prisoners for labor. On October thirtieth, one of them discovered the floor of the ancient building. Archeologist Yotam Tepper, the leader of the dig, called it "the find of a lifetime."

The floor is about six meters by nine meters. It is formed by two mosaics made from stones of different colors and shapes. One of the mosaics represents a traditional Christian symbol, a fish.

The mosaic also includes several messages. The Israeli Antiquities Authority says one appears to be from a Roman soldier. The message says he paid for the mosaic to seek honor. It also names the maker of the mosaic. Researchers say another message lists the names of four women as a remembrance.

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Archeologists say they also found what may have served as a base for a structure from which to lead religious services. Nearby is a third message, believed to say: "The God-loving Aketous has offered this table to the God Jesus Christ, as a memorial.?nbsp;

Pieces of cooking tools and containers for wine were also found on the floor of the structure. Mister Tepper says the pottery dates to the third century. He says the kind of Greek writing used in the messages also represents that time period.

And Mister Tepper says the design of the structure is simpler than those of churches that came after the third century.

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Experts in the history of Christianity generally believe that churches did not exist until the fourth century. Christianity was banned until Emperor Constantine of Rome made the religion legal in the year three-thirteen. Experts argue that it was too dangerous before then for Christians to worship in public, so they did so in secret.

As a result, one expert questions if a Roman soldier in the third century would have taken the risk to place a message on a mosaic in a church. He says such a violation of law, if discovered, would have meant the end of the man's service. It might have meant the end of the soldier, too.

One theory is that the church may have been established later than the Roman building that housed it.

The mystery of the ancient church should be settled in time. Archeologists say only about ten percent of the area has been uncovered so far. Israeli officials now have to decide how to deal with a valuable archeological site on the grounds of a prison.

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The government of Angola says the recent outbreak of Marburg fever there has ended. Health Minister Sebastao Veloso said last week that there have been no recorded cases of the disease since July.

 
 
The Marburg virus is spread through contact with bodily fluids. It can cause high body temperature, organ failure and severe bleeding. There is no cure.

The outbreak in Angola began last year in the northern province of Uige. The health minister says there were two hundred fifty-two cases. He says only twenty-five people, or ten percent, survived.

The World Health Organization had earlier estimates of more than three hundred deaths. Still, this was the worst outbreak recorded since laboratories first identified the Marburg virus in nineteen sixty-seven.

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SCIENCE IN THE NEWS was written by Jerilyn Watson and Caty Weaver. Cynthia Kirk was our producer. I'm Bob Doughty.

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And I'm Pat Bodnar. Internet users can read and listen to our programs at www.tingroom.com. Join us next week for more news about science in Special English on the Voice of America.