SCIENCE IN THE NEWS - Genetic Map of Chimps May Show What Ma

SCIENCE IN THE NEWS - Genetic² Map of Chimps⁴ May Show What Makes Us Human
By George Grow, Cynthia Kirk and Jerilyn Watson

Broadcast: Tuesday, September 20, 2005

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VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty⁵. This week, we tell about a possible new use for American alligators⁷. We also will tell how some American scientists have reacted to a report critical of homeopathic treatments.

VOICE ONE:

But first, a genetic map of an animal may show what makes us human beings.

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Scientists say people and chimpanzees developed separately since they split from a common ancestor about six million years ago. But studies have shown that chimpanzee genes⁸ are very similar to those of human beings.

Recently, an international team of scientists said it has prepared a partial genetic map of a chimp³. They found that ninety-six percent of the chimp genes are exactly the same as human genes. Scientists say the remaining four percent may help to explain what makes humans different from chimps. They also say knowing the genetic differences may prove useful in medical research.

VOICE TWO:

Studies of D.N.A. make it possible to understand the genetic relationships of all life on Earth. The letters D.N.A. represent deoxyribonucleic acid. Every cell of every living thing contains D.N.A. Scientists call it the chemical of life. All of the D.N.A. in cells is called the genome.

D.N.A. is made up of genes. Genes, like letters in words, carry a huge amount of information. These messages tell cells how to make all the materials for life.

Genes are carried on chromosomes¹⁰. Almost all human cells have forty-six chromosomes. There are hundreds of genes on each chromosome⁹. The chemicals that make up D.N.A. are nucleic acids. There are four kinds of nucleic acid: adenine, thymine, guanine and cytosine. These chemicals are called bases. They are represented by the letters A, T, G and C.

VOICE ONE:

Robert Waterston is the head of the Department of Genome Sciences at the University of Washington School of Medicine in Seattle, Washington. He directed the Chimpanzee Sequencing and Analysis Consortium Project.

America's National Human Genome Research Institute provided assistance for the study. The findings were reported in the two publications, Nature and Science.

Professor Waterston and his team studied the D.N.A. of a chimpanzee named Clint. Clint lived at the Yerkes National Primate¹¹ Research Center in Atlanta, Georgia, until he died of heart failure last year.

VOICE TWO:

The team of scientists made a map of the position of every one of Clint's genes. It then compared the chimp genes to the human genome. Human chromosomes have about three thousand million D.N.A. base pairs. Chimpanzees have about the same number.

The scientists found that only forty million base pairs differ between human and chimp. They say this means a generally small number of genetic differences are responsible for differences between people and chimpanzees. They also say the number of genetic differences between human and chimp is about ten times more than between any two persons.

VOICE ONE:

Professor Waterston and his team compared genes that control the activity of other genes. They found that the genes had changed quickly in human beings, but not in chimps.

Professor Waterston says the study strongly confirms the theories of the British nature scientist Charles Darwin. Darwin developed the theory of evolution that life on Earth developed through a process he called natural selection.

A separate study published in Science examined gene¹ activity in chimpanzees and humans. That study found that genes common to both appeared to have become more active in the brains of humans. But the activity of shared genes in the heart and other organs remained the same.

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VOICE TWO:

 
 
A large animal that lives in America's southern wetlands may provide a valuable substance with medical uses. American scientists are exploring ways to help people with collagen removed from dead alligators.

Jack¹² Losso and Mark Schexnayder work for the agriculture center at Louisiana State University. They are the lead investigators¹³ on the alligator⁶ collagen project.

Collagen is the most important protein in connective tissue. It holds cells together. It helps form bone and cartilage, the material that protects the ends of bones.

VOICE ONE:

The scientists say collagen from alligators could form replacement¹⁴ skin for burn victims. They say the collagen helps to heal wounds and stop bleeding. Doctors could also use it to treat some cancers, high blood pressure and the uncontrolled release of body wastes. The scientists say alligator collagen could also provide material for beauty products or foods.

Currently, collagen from cows and pigs is used in beauty products and for cooking. Mister Losso says scientists now are looking for other ways to get collagen because of concerns about mad cow disease. He and Mister Schexnayder say the protein also can be taken from sea creatures, including sharks.

VOICE TWO:

About two years ago, the Louisiana State University team started removing collagen from black drum and sheepshead fish. Masahiro Osawa of Japan designed the chemical process that enabled the removal. The team has asked the United States federal government for intellectual property protection for the process.

The team also compared alligator collagen and collagen from shark cartilage -- tissue that protects the ends of bones. The shark collagen is used in wound coverings, replacement for human skin or bone, and other material for medical operations. Mister Losso said the alligator and shark material are scientifically similar.

VOICE ONE:

In the United States, some alligators are killed for their meat. Their skin has considerable value for leather clothing, shoes and handbags. The state of Louisiana does not consider alligators endangered. State law permits limited harvesting of the animals.

The alligator parts that contain collagen are now usually thrown away. Louisiana alligators are responsible for more than four hundred fifty metric tons of unwanted parts each year. Destruction of this waste is costly¹⁵.

Several years ago, Mister Schexnayder was asked to invent a purpose for this waste that would bring a profit. So he and Mister Losso went to work and came up with the idea of removing collagen from the dead animals. The United States Department of Commerce provided money for the experiments.

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VOICE TWO:

Two weeks ago, we told you about a report critical of the medical value of homeopathic treatments. The report was published last month in The Lancet. It said that homeopathic treatments have the same effect as a placebo¹⁶. A placebo looks like medicine but contains no active substance.

A German doctor, Samuel Hahnemann, developed homeopathic medicine in the seventeen nineties. He believed that some substances could cure diseases if they produced effects similar to those of the disease itself. He believed that these substances -- from plants, minerals or animals -- helped the body's own defense¹⁷ system to fight the sickness.

VOICE ONE:

The National Center for Homeopathy provides information about homeopathy to people in the United States. Recently, the group reported that several American scientists have rejected the Lancet report.

One of them is Joyce Frye of the University of Pennsylvania. She also is president of the American Institute of Homeopathy. This group represents the country's homeopaths.

Professor Frye says the study was strongly influenced by the opinions of the researchers. She said the researchers seemed to begin their work with a strong personal judgment¹⁸, or bias¹⁹.

VOICE TWO:

Professor Frye said the study cleared showed effects of homeopathic treatments, but the researchers found ways to avoid them. She also said the main findings depended on a comparison of only a few studies: eight tests of homeopathy and six tests of traditional medicine.

Iris²⁰ Bell of the University of Arizona is another homeopath. She criticized the study for its methods of comparison. The researchers compared studies of homeopathic treatments with studies of medical drugs. Professor Bell says their methods are acceptable for studying traditional medicines, but not in comparing homeopathic treatments.

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VOICE ONE:

This program was written by George Grow, Cynthia Kirk and Jerilyn Watson. Our producer was Jill Moss²¹. I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty. Join us again next week at this time for another SCIENCE IN THE NEWS program in VOA Special English.

1 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

2 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

3 chimp   

n.黑猩猩

参考例句：

• In fact,the color of gorilla and chimp are light-color.其实大猩猩和黑猩猩的肤色是较为浅的。
• The chimp is the champ.猩猩是冠军。

4 chimps   

（非洲）黑猩猩( chimp的名词复数 )

参考例句：

• Chimps are too scarce, and too nearly human, to be routinely slaughtered for spare parts. 黑猩猩又太少，也太接近于人类，不可以作为人器官备用件说杀就杀。 来自英汉非文学 - 生命科学 - 医学的第四次革命
• And as nonprimates, they provoke fewer ethical and safety-related concerns than chimps or baboons. 而且作为非灵长类，就不会产生像用黑猩猩或狒狒那样的伦理和安全方面的顾虑。 来自英汉非文学 - 生命科学 - 医学的第四次革命

5 doughty   

adj.勇猛的，坚强的

参考例句：

• Most of successful men have the characteristics of contumacy and doughty.绝大多数成功人士都有共同的特质：脾气倔强，性格刚强。
• The doughty old man battled his illness with fierce determination.坚强的老人用巨大毅力与疾病作斗争。

6 alligator   

n.短吻鳄(一种鳄鱼)

参考例句：

• She wandered off to play with her toy alligator.她开始玩鳄鱼玩具。
• Alligator skin is five times more costlier than leather.鳄鱼皮比通常的皮革要贵5倍。

7 alligators   

n.短吻鳄( alligator的名词复数 )

参考例句：

• Two alligators rest their snouts on the water's surface. 两只鳄鱼的大嘴栖息在水面上。 来自辞典例句
• In the movement of logs by water the lumber industry was greatly helped by alligators. 木材工业过去在水上运输木料时所十分倚重的就是鳄鱼。 来自辞典例句

8 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

9 chromosome   

n.染色体

参考例句：

• Chromosome material with exhibits of such behaviour is called heterochromatin.表现这种现象的染色体物质叫做异染色质。
• A segment of the chromosome may become lost,resulting in a deletion.染色体的一个片段可能会丢失，结果产生染色体的缺失。

10 chromosomes   

n.染色体( chromosome的名词复数 )

参考例句：

• Chromosomes also determine the sex of animals. 染色体也决定动物的性别。 来自《简明英汉词典》
• Each of four chromosomes divide longitudinally. 四种染色体的每一种都沿着纵向分裂。 来自《现代汉英综合大词典》

11 primate   

n.灵长类（目）动物，首席主教；adj.首要的

参考例句：

• 14 percent of primate species are highly endangered.14%的灵长类物种处于高度濒危状态。
• The woolly spider monkey is the largest primate in the Americas.绒毛蛛猴是美洲最大的灵长类动物。

12 jack   

n.插座，千斤顶，男人；v.抬起，提醒，扛举；n.（Jake）杰克

参考例句：

• I am looking for the headphone jack.我正在找寻头戴式耳机插孔。
• He lifted the car with a jack to change the flat tyre.他用千斤顶把车顶起来换下瘪轮胎。

13 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

14 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

15 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

16 placebo   

n.安慰剂；宽慰话

参考例句：

• The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
• The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。

17 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

18 judgment   

n.审判；判断力，识别力，看法，意见

参考例句：

• The chairman flatters himself on his judgment of people.主席自认为他审视人比别人高明。
• He's a man of excellent judgment.他眼力过人。

19 bias   

n.偏见，偏心，偏袒；vt.使有偏见

参考例句：

• They are accusing the teacher of political bias in his marking.他们在指控那名教师打分数有政治偏见。
• He had a bias toward the plan.他对这项计划有偏见。

20 iris   

n.虹膜，彩虹

参考例句：

• The opening of the iris is called the pupil.虹膜的开口处叫做瞳孔。
• This incredible human eye,complete with retina and iris,can be found in the Maldives.又是在马尔代夫，有这样一只难以置信的眼睛，连视网膜和虹膜都刻画齐全了。

21 moss   

n.苔，藓，地衣

参考例句：

• Moss grows on a rock.苔藓生在石头上。
• He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。